# Safety Assessment of 

# Di(2-ethylhexyl)phthalate (DEHP) Released from PVC Medical Devices

Center for Devices and Radiological Health

U.S. Food and Drug Administration

12709 Twinbrook Parkway

Rockville, MD 20852

# 

TABLE OF CONTENTS

#  

Page

Executive Summary
.............................................................................................
3

1.  Introduction
    ..................................................................................................
    8

2.  Exposure Assessment
    ....................................................................................
    10

2.1 Parenteral Exposure to DEHP
.......................................................... 10

2.  Oral Exposure
    ..............................................................................
    17

3.  Inhalation Exposure
    .......................................................................
    18

4.  Dermal/Mucosal Exposure
    .............................................................. 19

5.  Aggregate Exposure to DEHP from Multiple Medical Devices
    ................ 20

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3.  Derivation of Tolerable Intake (TI) Values for DEHP
    ............................................ 21

3.1 Selection of Appropriate NOAEL and/or LOAEL Values from

Critical Studies (Step 1)
................................................................ 21

3.2 Derivation of a Modifying Factor (Step 2)
........................................... 30

#  3.3 Application of Modifying Factors to Derive Parenteral and Oral TI

#  Values (Step 3)......................................................................... 42

4.  Risk Characterization
    ......................................................................................
    44

4.1 Conclusions Based on TI/Dose Ratios
.................................................... 44

4.2 Conclusions Based on Other Considerations
............................................ 48

4.3 Aggregate Exposure to DEHP and MEHP
................................................ 48

5.0 References
...................................................................................................
49

Annex A: Exposure Assessment

Annex B: Summary of Results of Parenteral Toxicity Studies of DEHP

Annex C: Aggregate Safety Assessment for Coexposure to DEHP and MEHP

Annex D: Nonsystemic Effects

**TABLE OF TABLES**

Page

Table 2-1 PVC medical devices known to release DEHP
.......................................... 10

Table 2-2 Estimated upper-bound dose of DEHP received by adult and
neonatal

patients undergoing various medical procedures
....................................... 11

Table 2-3 Dose of DEHP received by neonates undergoing IV drug therapy
................. 13

Table 2-4 Dose of DEHP received from replacement transfusion in neonates
............... 15

Table 2-5 Dose of DEHP received during cardiac surgery
........................................ 16

Table 2-6 Dose of DEHP received by infants undergoing ECMO
............................... 16

Table 2-7 Aggregate exposure of neonates to DEHP in the NICU environment
............ 20

Table 3-1 Critical toxicity studies for DEHP
........................................................... 22

Table 3-2 Criteria to determine appropriateness of study for TI
derivation ................... 23

Table 3-3 Evaluation of critical toxicity studies (parental route) for
DEHP ..................... 29

Table 3-4 Uncertainty Factors for TI derivation
...................................................... 30

Table 3-5 Comparison of the potency of DEHP in rats and nonhuman
primates

following oral exposure (based on testicular effects)
................................. 35

Table 3-6 *In vitro* hydrolysis of phthalate diesters by intestinal cell
preparations ........... 36

Table 3-7 Comparison of experimental conditions used in Advamed (2001)
study and

conditions in the clinical setting for neonates in a NICU and adults

undergoing hemodialysis
..................................................................... 39

Table 3-8 Modifying Factors for derivation of TI values for DEHP
...........................\... 42

Table 3-9 TI values for DEHP
............................................................................
43

Table 3-10 Existing health-based exposure limits for DEHP based on
noncancer

effects (oral exposure)
........................................................................
43

Table 4-1 Comparison of Tolerable Intake (TI) values for DEHP to the
dose of

DEHP received by adult and neonatal patients undergoing various

medical procedures
............................................................................
47

Executive Summary

Patients undergoing medical procedures such as IV therapy, enteral and
parenteral nutrition support, blood transfusion, hemodialysis and
peritoneal dialysis, cardiopulmonary bypass (CPB) and extracorporeal
membrane oxygenation (ECMO) can be exposed to di-(2-ethylhexyl)phthalate
(DEHP), a compound used as a plasticizer for polyvinyl chloride (PVC)
medical devices. DEHP has been shown to produce a wide range of adverse
effects in experimental animals, notably liver toxicity and testicular
atrophy. Although the toxic and carcinogenic effects of DEHP have been
well established in experimental animals, the ability of this compound
to produce adverse effects in humans is controversial. As a result, the
ability of DEHP and other phthalate esters to produce adverse effects in
humans has been a topic of active discussion and debate in the
scientific and regulatory communities. Since patients undergoing medical
procedures can be exposed to DEHP, a safety assessment has been
conducted by the FDA Center for Devices and Radiological Health (CDRH)
to provide risk managers with information necessary for informed
regulatory decision making regarding the safety of DEHP released from
PVC medical devices. This safety assessment should be viewed as a first
step in this process. Other factors, such as the availability and safety
of alternatives to DEHP and PVC, must also be considered in developing a
risk management strategy to address this issue.

This Executive Summary provides a brief description of the approach used
to assess the risk posed by patient exposure to DEHP and describes the
conclusions reached following a careful examination of the data.

###### Safety Assessment Approach Used

No attempt has been made in this document to quantitatively assess the
risk posed by exposure of patients to DEHP. Instead, a safety assessment
approach involving comparison of the doses of DEHP received by patients
undergoing various procedures to Tolerable Intake (TI) values for DEHP
was used to develop a general index of safety or risk with regard to
patient exposure to DEHP. A TI value is defined as the dose of a
compound that is not expected to result in adverse effects following
exposure for a defined period. The process used to derive the TI values
for DEHP is outlined in ISO/DIS 10993-17 standard, *Method for the
Establishment of Allowable Limits for Leachable Substances.*

The approach used by FDA/CDRH to derive the TI values for DEHP is based
on an international consensus standard and is essentially identical to
the method used by other regulatory agencies and advisory bodies to
establish health-protective exposure levels for DEHP (and other
compounds). The approach used in this safety assessment can be
characterized as health-protective or conservative, since worst-case
estimates of dose are typically compared to TI values intended to be
protective for even sensitive individuals in the population. As a
result, the TI/dose comparisons derived for many clinical scenarios are
likely to overestimate the risk to the majority of the exposed patient
population.

***Exposure assessment and selection of a critical toxicity study***

A comprehensive review of the literature was undertaken to provide the
data used to estimate the dose of DEHP received by patients undergoing
various procedures and to identify the critical effects of DEHP in
exposed experimental animals. These data are summarized in the main body
of the safety assessment and more detailed exposure and toxicity
assessments can be found in Annexes A and B, respectively. The exposure
assessment was based on direct measurements of patient exposure to DEHP
and on estimates based on the rate at which DEHP was released from
various devices. In the latter case, every attempt was made to take into
account current clinical practices that impact device use and subsequent
patient exposure to DEHP.

The TI values for DEHP were derived from the results of studies
conducted using experimental animals and are based on adverse effects
produced by DEHP on the testes, an organ that appears to be particularly
sensitive to DEHP, at least in rodents. Justification for the selection
or rejection of the key toxicity studies is provided in the safety
assessment. In addition to the usual criteria applied in selecting a
critical study (e.g., adequate sample size, use of an appropriate
vehicle), consideration was given to what constitutes an "adverse"
effect with regard to DEHP toxicity, since a number of the effects
produced by DEHP can be considered to be adaptive or subclinical.
Although the parenteral TI value was based primarily on the results of
one study (AdvaMed, 2001), similar no-observed-adverse-effect-level
(NOAEL) and lowest-observed-adverse-effect-level (LOAEL) values were
identified in other relevant studies, thereby increasing the confidence
that the appropriate NOAEL in rodents was selected for this assessment.

***Derivation of a TI value for DEHP***

Uncertainty Factors (UFs) were applied to the NOAEL or LOAEL from the
critical studies to derive the TI values. These UFs are intended to
account for: 1) interspecies differences in the potency of DEHP, 2)
variability in the response of the human population to DEHP and 3)
deficiencies in the data available to derive the TI values. Explicit
identification of the uncertainties associated with the data helps to
define the magnitude of each UF and results in a more transparent
approach for assessing the risk posed by patient exposure to DEHP.
Application of UFs to the NOAEL from the AdvaMed (2001) study yields a
parenteral TI value of 0.6 mg/kg/day and an oral TI value of 0.04
mg/kg/day. Exposure of patients to DEHP at these doses by parenteral or
oral routes of exposure, respectively, is not expected to result in the
development of adverse effects. The oral TI is consistent with the
health-based exposure limit values for DEHP derived by the U.S. EPA,
Health Canada, the OECD, and the EU Scientific Committee on Toxicity,
Ecotoxicity and the Environment (CSTEE).

In addition to DEHP, patients can be exposed to the DEHP metabolite,
MEHP. This compound is formed exogenously by lipase enzymes in stored
plasma or blood or by hydrolysis in stored and heated IV fluid. As a
result, some of the DEHP that is released into stored blood, plasma, or
IV fluids will be converted to MEHP before reaching the patient.
Exposure to MEHP is important since this compound is thought to be the
toxic metabolite of DEHP and because it is more potent than DEHP in
producing adverse effects. A method was developed to estimate the
aggregate dose of DEHP and MEHP and to express this dose on the basis of
DEHP-equivalents (Annex C). However, because of uncertainties associated
with the relative potency of DEHP:MEHP and the resulting estimates of
DEHP-equivalent dose, the TI/dose ratios based on the dose of
DEHP-equivalents received by patients will not be used to support
regulatory decision making. Despite these uncertainties, it is
nevertheless important to point out that simultaneous coexposure to DEHP
and MEHP can occur in some patients.

The conclusions reached in the safety assessment are based solely on the
potential for DEHP to cause adverse systemic effects in exposed
patients. However, the clinical significance of various nonsystemic
effects produced by DEHP is explored in Annex D. For example, the
ability of DEHP to alter the hemocompatibility of PVC tubing or result
in adsorption of drugs to PVC tubing may be the most clinically
important endpoints to consider in the risk management phase of the
assessment, depending on the device.

###### Conclusions of the Safety Assessment

The following conclusions were reached by comparing the dose of DEHP by
patients undergoing various medical procedures to the TI value for oral
or parenteral exposure. Comments on the size of the exposed population
are included, in some cases, since the size of the impacted population
is a factor in determining the risk management options to be considered.

######### IV infusion of crystalloid fluids and drugs

Based on the results of the safety assessment, CDRH concludes that there
is little to no risk posed by patient exposure to the amount of DEHP
released from PVC IV bags following infusion of crystalloid fluids
(e.g., normal saline, D5W, Ringers Lactate). Further, there is little
risk posed by exposure to the amount of DEHP released from PVC bags used
to store and administer drugs that require a pharmaceutical vehicle for
solubilization, when label instructions are followed.

***Total Parenteral Nutrition (TPN)***

The dose of DEHP received by adult patients receiving TPN admixtures is
estimated to be less than the TI, suggesting that there is little
concern for DEHP-mediated effects in these patients. In addition,
non-PVC bags and tubing are typically used to administer TPN, further
lessening the concern about DEHP-mediated effects.

The dose of DEHP received by neonates undergoing TPN supplementation is
uncertain. The results of one study suggest that neonates can receive a
very high dose of DEHP, whereas another suggests that neonates receive
doses of DEHP from TPN that are equivalent to the TI. Therefore,
depending on the data used to derive the TI/dose ratio, neonates
receiving TPN admixtures with lipid may be at increased risk of
DEHP-mediated adverse effects.

##### *Blood transfusion*

Relatively high doses of DEHP can be received by patients who are
transfused with large volumes of blood and blood products over a short
period (e.g., trauma or surgical patients receiving massive
transfusions). However, the TI/dose ratio for this procedure is likely
to overestimate the actual risk to these patients, since the TI is
intended to be protective for long-term exposures, compared to
relatively short-term exposure in acute transfusions. In contrast, a
patient undergoing a routine, elective surgical procedure typically
receives about two units of packed red blood cells. Transfusion of this
volume of blood will result in a DEHP dose equivalent to the TI value,
approximately 0.5 mg/kg/day. Long-term transfusion of blood to patients
with anemia results in a DEHP dose about an order of magnitude lower.
Similarly, infants who receive replacement transfusions in the NICU
receive relatively small DEHP doses from the transfusions. Apheresis
donors are exposed to relatively little DEHP when the dose is
time-averaged over an extended period. Consequently, there is little
concern about DEHP-associated adverse effects developing in persons
donating platelets or plasma.

Two subpopulations of patients that may be at increased risk from
exposure to DEHP following transfusions are infants undergoing exchange
transfusion and adults undergoing ECMO. However, neither of these
procedures is done very often, so the patient population exposed to
relatively large doses of DEHP via exchange transfusion or replacement
transfusion of adults on ECMO is expected to be small.

##### *Cardiopulmonary bypass and ECMO*

The aggregate dose of DEHP received by adults undergoing cardiopulmonary
bypass procedures may equal or exceed the TI in some patients. However,
heparin-coated tubing is used in about half of "special" or high risk
cases and about 17% of "routine" cases (Mejak et al., 2000). Since
little DEHP is released from heparin-coated tubing (Karle et al., 1997),
the dose of DEHP received by many patients undergoing cardiopulmonary
bypass will be less than those undergoing the procedure where uncoated
PVC tubing is used.

The dose of DEHP received by neonates undergoing ECMO may exceed the
parenteral TI by more than 20-fold, based on the exposure estimate from
one study. However, a TI/dose close to 1 for this procedure can be
derived using dose information from another study. Therefore, the risk
posed by patient exposure to the amount of DEHP released during ECMO is
uncertain. It is important to point out that no acute effects were seen
in neonates undergoing this procedure in the recent study by Karle et
al. (1997); however, it is equally important to point out that
testicular toxicity (the assumed most sensitive effect in humans and
other species) was not assessed in this study.

##### *Hemodialysis and peritoneal dialysis*

Based on recent data on the amount of DEHP retained by patients on
hemodialysis, there is little concern regarding exposure to DEHP in
patients undergoing this procedure. In addition, since very little DEHP
is released into peritoneal dialysis fluid, the corresponding risk of
systemic effects developing following exposure to this low dose of DEHP
is also low.

##### *Enteral nutrition and breastfeeding*

Lipid in enteral nutrition solutions can leach out considerable doses of
DEHP from PVC bags and tubing. As a result, these patients may be at
increased risk of developing DEHP-mediated effects if PVC bags and
tubing are used to deliver the enteral nutrition solutions.

Based on theoretical estimates, it is possible for nursing infants of
mothers on hemodialysis to receive very high doses of DEHP; however the
exact dose received by these babies is highly uncertain. Because of the
level of uncertainty in this estimate, a TI/Dose ratio was not derived
for this means of exposure to DEHP. Also, because women on hemodialysis
are typically infertile, the population of infants exposed in this
manner is thought to be very small.

Bags used to store breast milk following the use of a breast pump are
typically made from polyethylene or nylon coated with polyethylene.
Consequently, it is not expected that infants will be exposed to any
DEHP released from a breast pump or milk storage bags.

***Aggregate exposure to DEHP from multiple medical devices***

DEHP dose estimates typically do not take into account exposure of
patients to multiple PVC devices. Consequently, it is important to
assess the potential risk of patients in various clinical scenarios by
taking into account aggregate exposure to DEHP from multiple devices.
For example, neonates in the NICU environment are exposed to DEHP from
multiple devices. Based on the dose of DEHP received in such procedures
as intravenous administration of sedatives, administration of TPN and
replacement transfusion, all common procedures in the NICU, it is
possible to estimate that a 4 kg infant could receive a DEHP dose on the
order of 3 mg/kg/day for a periods of weeks or months. The resulting
TI/dose ratio in this setting is 0.2. In other words, the dose of DEHP
received by some infants from device-related sources could be 5-fold
greater than the TI. If the neonate is also undergoing ECMO treatment,
the TI/dose ratio drops to around 0.05, indicating that the dose of DEHP
received by some infants from device-related sources could be 20-fold
greater than the dose of DEHP that is not expected to result in adverse
effects following intravenous exposure.

######## Are children at increased risk for the adverse effects of DEHP, relative to adults?

Executive Order 13045, issued on April 27, 1997, directs relevant
Federal agencies to make it a high priority to identify and assess
environmental health risks that may disproportionately affect children
and ensure that its policies, programs, and standards address
disproportionate risks to children from environmental health risks or
safety risks. Accordingly, FDA/CDRH has examined this issue and has
concluded that **children undergoing certain medical procedures may
represent a population at increased risk for the effects of DEHP.** This
decision is supported by three findings: 1) children undergoing some
medical procedures receive a greater dose of DEHP, on a mg/kg basis,
than adults do, 2) pharmacokinetic differences between children and
adults may result in greater absorption of DEHP, greater conversion of
DEHP to MEHP (the toxic metabolite of DEHP), and reduced excretion of
MEHP in children compared to adults, and 3) children may be more
pharmacodynamically sensitive to the adverse effects of DEHP than adults
are. This conclusion is consistent with that reached by the expert panel
that was recently convened by the Center for the Evaluation of Risks to
Human Reproduction (CERHR) of the National Toxicology Program.
Specifically, the panel noted that: "The available reproductive and
developmental toxicity data and the limited but suggestive human
exposure data indicate that human exposures in this situation approach
toxic doses in rodents, which causes the Panel serious concern that
exposure may adversely affect male reproductive tract development."

**1.0 Introduction**

Polyvinyl chloride (PVC) plastic is used to manufacture a number of
medical devices, including IV and blood bags and infusion tubing,
enteral and parenteral nutrition feeding bags, nasogastric tubes,
peritoneal dialysis bags and tubing, and tubing used in devices for
cardiopulmonary bypass (CPB), extracorporeal membrane oxygenation
(ECMO), and hemodialysis. Unplasticized PVC is hard and brittle at room
temperature. As a result, plasticizers are necessary to impart
flexibility to the polymer. Various plasticizers (e.g., adipates,
citrates, phthalates) have been used as plasticizers for PVC, but the
plasticizer of choice for PVC medical devices is di-(2-ethylhexyl)
phthalate (DEHP).

The potential for (DEHP) and other phthalate esters to produce adverse
effects in humans has been the subject of considerable discussion and
debate in the scientific community, as well as attention by the media.
Although the toxic and carcinogenic effects of DEHP have been well
established in experimental animals, the ability of this compound to
produce these effects in humans is controversial.

Concerns over the potential adverse effects of DEHP in patients have
prompted one group, Health Care Without Harm (HCWH), to submit a
Citizens' Petition to the FDA Commissioner requesting that the agency
initiate action to require labeling on PVC medical devices to warn users
that these devices may expose patients to DEHP and to establish a
program to expedite the development and usage of substitutes for PVC
devices that leach phthalate esters. In addition, various expert panels
have recently been convened to examine the likelihood that exposure to
DEHP could result in the development of adverse effects in humans,
including a panel convened under the auspices of the American Council on
Science and Health (ACSH), chaired by Dr. C. Everett Koop and a panel
convened by the National Institute of Environmental Health Sciences'
(NIEHS) Center for the Evaluation of Risks to Human Reproduction
(CERHR). The FDA Center for Biologics Evaluation and Research (CBER)
also recently held a workshop to examine issues relating to the use of
phthalates as plasticizers for blood storage bags.

The various panels described above have been convened largely to address
a series of controversial issues regarding the potential health risk
posed by human exposure to DEHP. Following a review of the available
data, these groups have reached differing opinions regarding the health
risk posed by exposure to DEHP. For example, expert panel chaired by Dr.
Koop for the ACSH concluded that there is little or no harm posed by
patient exposure to DEHP. This conclusion was also reached by trade
groups associated with the manufacture of PVC medical devices or the
production of phthalate esters, such as the Health Industry
Manufacturers Association (HIMA), the Phthalate Esters Panel of the
Chemical Manufacturers Association (CMA), the Vinyl Institute, and the
American Plastics Council. In contrast, the expert panel convened by the
CERHR felt that exposure of critically ill neonates to DEHP represented
a "serious concern" and HCWH has concluded that the potential risks of
associated with patient exposure to DEHP are significant enough to
require regulatory initiatives including labeling of PVC devices and to
move toward alternatives to PVC. Over the years, a number of individual
investigators have also suggested that DEHP exposure may pose a risk to
patients, whereas others have suggested that there is little or no risk,
particularly with regard to the carcinogenic effects of DEHP.

The divergent opinions on the safety of DEHP are due, in part, to
differences in the interpretation of the scientific data and, in part,
to differences in philosophical approach toward safety. Industry, in
part, points to the lack of effects observed in DEHP-exposed patients as
evidence of the safety of DEHP, along with data that suggest that the
mechanism by which DEHP exerts certain effects in rodents is not
applicable to humans. In contrast, groups such as HCWH embrace a
precautionary approach that argues that patient exposure to DEHP should
be minimized in light of adverse effects seen in experimental animals
exposed to DEHP. However, neither of these approaches necessarily
involves comparison of the dose of DEHP received by patients undergoing
certain medical procedures to a Tolerable Intake (TI) value for DEHP.
Such an approach was used in this safety assessment. This safety
assessment has been prepared to provide risk managers with information
necessary for informed regulatory decision making regarding the safety
of DEHP released from PVC medical devices.

######## Safety Assessment Approach Used

No attempt has been made in this document to quantitatively assess the
risk posed by exposure of patients to DEHP. Instead, a safety assessment
approach involving comparison of the doses of DEHP received by patients
undergoing various procedures to Tolerable Intake (TI) values for DEHP
was used to develop a general index of safety or risk with regard to
patient exposure to DEHP. A TI value is defined as the dose of a
compound that is not expected to result in adverse effects following
exposure for a defined period. The process used to derive the TI values
for DEHP is outlined in ISO/DIS 10993-17, *Method for the Establishment
of Allowable Limits for Leachable Substances*, and is described more
fully in Section 3.0. Briefly, this process consists of three steps:

**Step 1**: Identification of data from critical studies to serve as the
basis for the selection of no-

observed-adverse-effect-level (NOAEL) and lowest observed adverse
effect-level

(LOAEL).

**Step 2:** Derivation of Uncertainty Factors (UFs) to account for: 1)
variability in response in the

human population, 2) differences in the potency of DEHP between
experimental animals

and humans, and 3) various other limitations in the database.

**Step 3:** The NOAEL and LOAEL values selected from the critical
studies were then divided by

the product of the UFs (known as the Modifying Factor) to derive the TI.

Justification for the selection of the critical studies and uncertainty
factors is provided in Section 3.0. Tables summarizing the results of
all of the studies considered for TI derivation are provided in Annex B.
Other potentially clinically significant effects (e.g., DEHP-mediated
effects on hemocompatibility of blood tubing, drug adsorption to PVC
tubing) are also discussed briefly in Section 3.0.

To characterize patient risk from exposure to DEHP, the dose of DEHP
received by patients undergoing various procedures (estimated in Section
2.0) is compared to the TI values for DEHP (estimated in Section 3.0).
The results of this risk characterization process, which is described in
Section 4.0, will allow CDRH to draw conclusions about the risk posed by
patient exposure to DEHP in various clinical scenarios.

2.  **Exposure Assessment**

DEHP is released from a wide variety of PVC medical devices. A partial
list of these devices is provided in Table 2-1.

Table 2-1. PVC medical devices known to release DEHP

  ----------------------------------- -----------------------------------
  IV storage bags                     Ventilator tubing

  IV infusion sets                    Endotracheal tubes

  IV infusion catheters               Nasogastric tubes

  Blood storage bags                  Enteral and parenteral nutrition
                                      storage bags

  Blood administration sets           Urinary catheters

  PVC exam gloves                     Suction catheters

  Chest tubes                         Nasal cannula tubing

  Hemodialysis tubing                 Syringes

  Extracorporeal membrane oxygenation Cardiopulmonary bypass (CPB) tubing
  (ECMO) tubing                       
  ----------------------------------- -----------------------------------

In this section, an attempt is made to quantify the dose of DEHP
received by patients undergoing various medical procedures. In most
cases, exposure is represented as administered dose (mg/kg/day) and is
time-averaged over a course of treatment. For example, if an adult
patient receives 60 mg of DEHP in a hemodialysis session, and undergoes
hemodialysis three times per week, the time-averaged dose of DEHP
received by this patient would be 60 mg/session x 3 sessions/week x
week/7 days x 1/70 kg = 0.37 mg/kg/day. It is necessary to represent
exposure dose in units of mg/kg/day, time-averaged over the exposure
period, so a common dose metric exists for comparison of the dose of
DEHP received by patients and the TI values for DEHP.

This section briefly provides the rationale for the selection of the
doses used to develop the TI/dose ratios presented in Section 4.0, Risk
Characterization. A more complete assessment of patient exposure to DEHP
can be found in Annex A..

**2.1 Parenteral Exposure to DEHP**

Parenteral exposure to DEHP can occur following intravenous infusion of
crystalloid solutions (e.g., normal saline, D5W, Ringers Lactate) and
drugs, administration of enteral nutrition and total parenteral
nutrition (TPN) solutions, and transfusion of blood or blood products.
In addition, patients undergoing cardiopulmonary bypass (CPB),
extracorporeal membrane oxygenation (ECMO), hemodialysis or peritoneal
dialysis can also be exposed to DEHP. The extent to which DEHP is
released from PVC medical devices is largely a function of the
lipophilicity of the fluid that comes into contact with the device.
Substances like blood, plasma, red blood cell or platelet concentrates;
IV lipid emulsion or total parenteral nutrition solution; and
formulation aids (e.g., Polysorbate 80) used to solubilize IV
medications can readily extract DEHP from PVC tubing and containers. In
contrast, nonlipid-containing fluids, like crystalloid IV solutions,
saline priming solution for ECMO and hemodialysis, and peritoneal
dialysis solution, extract relatively small amounts of DEHP from the PVC
constituents of the device. Estimates of the upper-bound doses of DEHP
received by patients undergoing various medical procedures are provided
in Table 2-2.

**Table 2-2. Estimated upper-bound dose of DEHP received by adult and
neonatal patients undergoing various medical procedures.**

+----------------------------------------+---------------+------------+
| Procedure                              | DEHP dose     |            |
|                                        |               |            |
|                                        | (mg/kg/day)   |            |
+----------------------------------------+---------------+------------+
|                                        | Adult (70 kg) | Neonate (4 |
|                                        |               | kg)        |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| **Infusion of crystalloid IV           | 0.005         | 0.03       |
| solutions**                            |               |            |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| **IV infusion of drugs requiring       |               |            |
| pharmaceutical vehicles for            |               |            |
| solubilization**                       |               |            |
+----------------------------------------+---------------+------------+
| When administered according to         | 0.04          | 0.03       |
| manufacturer's instructions            |               |            |
+----------------------------------------+---------------+------------+
| When stored mixed and stored at room   | 0.15          |            |
| temperature for 24 hr                  |               |            |
+----------------------------------------+---------------+------------+
| ########                               |               |            |
+----------------------------------------+---------------+------------+
| ######## TPN administration            |               |            |
+----------------------------------------+---------------+------------+
| Without added lipid                    | 0.03          | 0.03       |
+----------------------------------------+---------------+------------+
| With added lipid                       | 0.13          | 2.5        |
+----------------------------------------+---------------+------------+
| Administered via EVA bag and PVC       | 0.06          |            |
| tubing                                 |               |            |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| ######## Blood transfusion             |               |            |
+----------------------------------------+---------------+------------+
| Trauma patient                         | 8.5           |            |
+----------------------------------------+---------------+------------+
| Transfusion/ECMO in adult patient      | 3.0           |            |
+----------------------------------------+---------------+------------+
| Exchange transfusion/neonate           |               | 22.6       |
+----------------------------------------+---------------+------------+
| Replacement transfusion/neonate in     |               | 0.3        |
| NICU                                   |               |            |
+----------------------------------------+---------------+------------+
| Replacement transfusion/correction of  | 0.09          |            |
| anemia in                              |               |            |
|                                        |               |            |
| patients receiving chemotherapy and in |               |            |
| patients                               |               |            |
|                                        |               |            |
| with sickle cell disease               |               |            |
+----------------------------------------+---------------+------------+
| Replacement transfusion/surgical       | 0.28          |            |
| patient                                |               |            |
|                                        |               |            |
| undergoing CABG                        |               |            |
+----------------------------------------+---------------+------------+
| Treatment of clotting disorders with   | 0.03          |            |
| cryoprecipitate                        |               |            |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| ######## Cardiopulmonary bypass        |               |            |
+----------------------------------------+---------------+------------+
| CABG                                   | 1             |            |
+----------------------------------------+---------------+------------+
| Orthotopic heart transplant            | 0.3           |            |
+----------------------------------------+---------------+------------+
| Artificial heart transplant            | 2.4           |            |
+----------------------------------------+---------------+------------+
| ########                               |               |            |
+----------------------------------------+---------------+------------+
| ######## ECMO                          |               | 14         |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| ######## Apheresis                     | 0.03          |            |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| ###### Hemodialysis                    | 0.36          |            |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| **Peritoneal dialysis**                | \< 0.01       |            |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| **Enteral nutrition**                  | 0.14          | 0.14       |
+----------------------------------------+---------------+------------+

**2.1.1 Intravenous solutions**

In the absence of lipid-containing substances, the amount of DEHP that
leaches from PVC storage bags into crystalloid IV solutions is generally
very small. For example, little or no DEHP was found to leach into
crystalloid solution (normal saline, D5W) stored in PVC bags for more
than one year (Dine et al., 1991).

The upper-bound concentration of DEHP in crystalloid IV solutions, as
reported by Corley et al. (1977) for non-agitated bags (0.344 mg/day)
was used to develop the adult TI/Dose ratios for this procedure. Based
on this value, the time-averaged dose of DEHP delivered to a 70 kg
patient receiving 2 L of IV solution/day would be on the order of 0.005
mg/kg/day.

Neonatal patients do not typically receive IV fluid administration via a
gravity feed, rather a syringe infusion pump is often used to administer
IV fluids to pediatric patients. Although the syringe used is typically
made from polypropylene, a small amount of DEHP can be released from the
PVC administration tubing. Loff et al. (2000) found that infusion of a
crystalloid IV solution through PVC tubing for 24 hours yielded a DEHP
dose of 116 μg, equivalent to a dose of 0.03 mg/kg/day for a 4 kg
neonate.

**2.1.2 Intravenous administration of lipophilic drugs dissolved in
pharmaceutical solvents**

The package insert labeling that accompanies a number of drug products,
notably antineoplastics (e.g., paclitaxel, docetaxel, tacrolimus,
teniposide), cautions against the use of PVC containers and
administration sets for delivery of the drug. If non-PVC containers and
non-PVC infusion sets are used to administer the drug, DEHP exposure is
expected to be minimal.

The labeling information provided with a number of other drugs
(ciprofloxacin, cefoperazone sodium, fluconazole, metronidazole HCl,
cimetidine) instructs the user to administer and store the reconstituted
drug in PVC bags that release minimal amounts of DEHP, such as Baxter's
PL-146 bag. The concentration of DEHP in these bags is assumed to not
exceed 5 ppm (5 μg/ml). Based on the dosage requirements of the drug,
the dose of DEHP received by patients receiving these drugs in PL-146
bags is not expected to exceed 3 mg/day (0.04 mg/kg/day), assuming the
premixed solution is agitated for 24 hours at room temperature before
administration to the patient. Since IV bags are not typically agitated
for 24 hours, the actual DEHP dose received by most patients treated
with these drugs will be much less.

Often, multiple drugs are co-infused in the same IV infusion. One such
case is the co-infusion of quinine along with multivitamin preparations.
Faouzi et al. (1999a) demonstrated little DEHP is released from PVC bags
containing quinine alone in solution; however, the presence of the
lipophilic multivitamin cocktail dramatically increased the extent of
DEHP release from the bag. Following storage of quinine/multivitamin
combinations for 48 hours at 45^o^C, the concentration of DEHP in the
bags reached 21 μg/ml. Consequently, a patient receiving a 500 ml
infusion of quinine with a multivitamin cocktail would receive 10.8 mg
of DEHP, or 0.15 mg/kg/day for a 70 kg adult. Since the storage of
drug-containing IV solutions at 45^o^C is unlikely, this value
represents an upper-bound estimate of the amount of DEHP received by
adults during IV drug administration.

Drug infusions are typically administered to pediatric patients using an
infusion pump. Loff et al. (2000) measured the amount of DEHP that could
be received by a pediatric patient receiving IV drug therapy (Table
2-3).

**Table 2-3. Dose of DEHP received by neonates undergoing IV drug
therapy (Loff et al., 2000)**

+-----------+-----------+-----------+-----------+-----------+-----------+
| **Drug**  | **        | **Concen  | #         | **Total   | **Total   |
|           | Perfusion | tration** | ##### Amo | Amount of | Dose of   |
|           | time      |           | unt in ml | DEHP      | DEHP      |
|           | (hours)** | **of DEHP |           | (μg)**    | (m        |
|           |           | after     |           |           | g/kg/day) |
|           |           | perfusion |           |           | for a 4   |
|           |           | (μg/ml)** |           |           | kg        |
|           |           |           |           |           | neonate** |
+-----------+-----------+-----------+-----------+-----------+-----------+
| Imipenem  | 0.5       | 0.78      | 8         | 6.26      | 0.0015    |
+-----------+-----------+-----------+-----------+-----------+-----------+
| Midazolam | 24        | 1.13      | 24        | 26.4      | 0.007     |
+-----------+-----------+-----------+-----------+-----------+-----------+
| Fentanyl  | 24        | 4.59      | 29        | 132.5     | 0.033     |
+-----------+-----------+-----------+-----------+-----------+-----------+
| Propofol  | 24        | 656       | 10        | 6561      | 1.64      |
+-----------+-----------+-----------+-----------+-----------+-----------+

As shown in Table 2-3, relatively little DEHP is expected to be received
by children undergoing drug therapy with imipenem, midazolam or
fentanyl. In contrast, patients receiving propofol can receive a
considerable dose of DEHP over a 24 hour period. However, propofol is
not approved for sedation in pediatric ICU patients in the US (FDA,
2001). Therefore, for the purpose of this assessment, the upper-bound
dose of DEHP received by neonates undergoing conscious sedation is
assumed to be 0.03 mg/kg/day for a 4 kg infant, based on the DEHP dose
received during fentanyl infusion.

### 2.1.3 Parenteral nutrition

Total parenteral nutrition (TPN) formulations are often administered to
critically ill patients requiring nutritional supplementation.
Parenteral administration involves infusion directly into the
circulatory system. Typical TPN admixtures contain amino acids,
dextrose, electrolytes and lipids. Mazur et al. (1989) have shown that
the presence of lipid in the TPN solution increases the concentration of
DEHP in the admixture when PVC bags are used. The estimated daily dose
of DEHP received by an adult patient receiving 3 L of TPN admixture that
is either lipid-free or that has a lipid concentration of 10% is 0.03
and 0.13 mg/kg/day, respectively.

Although PVC storage bags are still used for TPN administration, EVA
(ethylvinyl acetate) bags are being increasingly used for this
application. However, even EVA bags contain PVC components (Kambia et
al., 2001), resulting in the release of some DEHP into the TPN solution.
In addition, although plasticizer-free tubing can be used gravity
infusion of lipid emulsions, the use of PVC tubing is required for pump
assisted lipid administration. Pump-assisted administration is necessary
to overcome hyperalimentation fluid-lipid density differences and
variable central venous back pressures. Therefore, it is possible that a
considerable amount of DEHP could be received by patients receiving TPN
even though non-PVC bags are used to store the TPN solution. The amount
of DEHP released into TPN solution stored for 24 hours in EVA bags
ranged from 0.2 to 0.7 mg (Kambia et al., 2001); 0.8 to 2 mg was
released from the bag and the PVC administration set, following flow of
the emulsion through the tubing for 11 hours. Assuming the highest
amount of DEHP released from the outlet of the tubing came from
emulsions containing the highest concentrations of DEHP, then the amount
of DEHP released from the tubing ranged from 0.6 to 1.3 mg/day, based on
administration for 11 hours/day. Based on these values, up to 2.8 mg of
DEHP could presumably be released from the tubing over a 24-hour
infusion and up to 4.4 mg of DEHP total (EVA bag + tubing) could be
received over a 24-hour period (equivalent to 0.06 mg/kg/day for a 70 kg
adult).

Unlike adults or even older children, neonates typically receive TPN via
a syringe infuser. Loff et al. (2000) recently reported that if PVC
tubing is used to administer the TPN, an infant could receive over 10 mg
of DEHP from the tubing over a 24-hour period (equivalent to 2.5
mg/kg/day for a 4 kg neonate). However, an upper-bound dose of DEHP
received by neonates can be derived from the data reported by Kambia et
al. (2001) as follows: 1600 ng/ml (maximum conc. of DEHP measured at
outlet of PVC tubing) x 150 ml/kg/day (upper-bound dose rate for
administration of TPN to neonates) = 0.24 mg/kg/day.

### 2.1.4 Transfusion of blood and blood products

DEHP migrates from PVC storage bags and into blood and blood products
(platelets, plasma, packed red blood cells) because of the lipophilic
nature of these biological fluids and cells. To derive appropriately
protective TI/Dose ratios, upper-bound concentrations of DEHP were used
to derive administered dose estimates.

Current clinical practices in transfusion medicine have been taken into
account in deriving these administered dose estimates. For example,
whole blood is rarely administered clinically. Instead, patients usually
receive RBCs, platelets, fresh frozen plasma (FFP) or some combination
of these products. When estimating the dose of DEHP received by patients
receiving blood or blood products, it is important to differentiate
between two scenarios: 1) infusion of large amounts of blood or blood
products over a short period and 2) chronic infusion of smaller volumes
of blood over a prolonged period. Acute, large-volume blood transfusion
is necessary in the treatment of acute blood loss in trauma patients,
some patients undergoing surgery, patients with acute gastrointestinal
bleeding and neonates undergoing exchange transfusion. Chronic
administration of smaller volumes of blood or blood products is common
in the treatment of patients with chemotherapy-associated anemia, blood
disorders such as leukemia and aplastic anemia, and in the treatment of
patients with clotting disorders.

Based on the results reported by other investigators, Sjoberg et al.
(1985b) estimated that an adult receiving 2.5 L of blood stored for 21
days would receive a DEHP dose of 1.3 to 2.6 mg/kg. In cases of massive
blood loss and transfusion of large amounts of blood, considerably more
DEHP could be administered to a patient. For example, Jaeger and Rubin
(1972) estimated that a gunshot victim receiving 63 units of blood would
receive a DEHP dose of around 8.5 mg/kg. This value represents an
upper-bound estimate of the dose of DEHP that is likely to be infused
during short-term transfusion scenario. It is important to recognize
that the actual dose of DEHP received by most critically injured
patients from transfusion will be much less.

Patients on ECMO receive RBCs to correct anemia and they receive
platelet concentrates, FFP, and cryoprecipitate to treat clotting
disorders. It is possible for adult patients to receive over 600 units
of blood products during the course of their ECMO treatment and
hospitalization. Based on the concentration of DEHP in blood and blood
products, it is possible for adults patients on ECMO to receive DEHP
doses on the order of 3 mg/kg/day or greater, solely from the blood
transfusions necessary to correct anemia and clotting disorders in these
patients.

Infants receiving exchange transfusion could receive a DEHP dose up to
22.6 mg/kg, according to Plonait et al. (1993); however, the DEHP dose
received by infants in the Sjoberg et al. (1985b) studies ranges from
0.84 to 4.22 mg/kg. It should be noted that exchange transfusion was
once commonly performed for the treatment of hyperbilirubinemia,
however, is rarely used today.

Critically ill neonates require repeated phlebotomies that may deplete
their blood volume. Also, infants are susceptible to anemia of
prematurity. As a result, critically ill neonates often require
transfusions. Levy et al. (1993) reported that 80% of low birthweight
infants in the United States will receive multiple transfusions. Ringer
et al. (1998) reported that neonates in one neonatal intensive care unit
(NICU) received, on average, 33.6 ml of RBCs and 2.4 ml of FFP in the
first 14 days. Infants in this study weighed about 1 kg. The dose of
DEHP received by neonates undergoing replacement transfusion with packed
RBCs is shown in Table 2-4.

##### Table 2-4. Dose of DEHP received from replacement transfusion in neonates 

+---------------+-------------+---------------+----------------------+
| **Blood       | **          | **Estimated   | **DEHP dose^3^**     |
| product**     | Volume^1^** | DEHP          |                      |
|               |             | con           | **(mg/kg/day)**      |
|               | **(ml)**    | centration^2^ |                      |
|               |             | (μg/ml)**     |                      |
+---------------+-------------+---------------+----------------------+
|               |             |               |                      |
+---------------+-------------+---------------+----------------------+
| RBCs          | 33.6        | 123.1         | 0.3                  |
+---------------+-------------+---------------+----------------------+
|               |             |               |                      |
+---------------+-------------+---------------+----------------------+
| FFP           | 2.4         | 26.7          | 0.004                |
+---------------+-------------+---------------+----------------------+
|               |             |               |                      |
+---------------+-------------+---------------+----------------------+

^1^Mean volume infused over 14 days in one of two NICUs

^2^Upper-bound concentration as reported by Plonait et al. (1993) for
packed cells and by Shintani

\(1985\) for FFP

^3^Assumes mean body weight of 1.073 kg per Ringer et al. (1998)

Since blood used for replacement transfusions is typically drawn up from
the storage bag with a syringe and injected into the patient, there is
no need to account for DEHP released from infusion sets. However, if
blood products are administered via an infusion pump, then the amount of
DEHP received by a pediatric patient would be considerably greater. For
example, Loff et al. (2000) found that up to 8.1 mg of DEHP was released
from PVC infusion tubing following perfusion of 20 ml of fresh frozen
plasma through the tubing for 1 hour. This would result in a DEHP dose
of around 2 mg/kg/day for a 4 kg child.

Patients with some chronic illnesses and those receiving antineoplastic
chemotherapy often become anemic and require blood transfusion. Jacobson
et al. (1977) determined that patients with leukemia and aplastic anemia
receiving red cells, whole blood, and platelets over the course of one
year received a DEHP dose of 0.006 to 0.08 mg/kg/day, when the dose was
time averaged over the year-long administration period. Patients with
sickle cell disease are typically transfused with 1-2 units of packed
cells every 2-4 weeks. Using the data from Plonait et al. (1993) as an
upper-bound value for the concentration of DEHP in packed red cells (174
μg/ml), the dose of DEHP received by a patient with sickle cell disease
would be approximately 0.09 mg/kg/day.

Anemia is a common problem in patients undergoing chemotherapy for
cancer treatment. As discussed by Barrett-Lee et al. (2000), 33% of
patients receiving chemotherapy will require blood transfusion during
their course of treatment. Estrin et al. (1999) reported that an average
of 5.1 red blood cell units were infused per patient undergoing
chemotherapy. The upper-bound estimate of DEHP exposure in this scenario
is about 0.03 mg/kg/day.

Cryoprecipitates containing clotting factors are administered to
patients with clotting disorders. Marcel (1973) found that
cryoprecipitate packs contained from 0.8 to 1.9 mg of DEHP each. Since
patients with clotting disorders can receive up to 400 bags of
cryoprecipitate in one year, the daily DEHP dose received by these
patients is on the order of 0.03 mg/kg/day.

Patients undergoing routine, elective surgical procedures typically
receive about two units of blood or blood products (Mallett et al.,
2000). Assuming a mean DEHP concentration of 44.8 μg/ml for packed cells
(Plonait et al., 1993) and a packed cell volume of 350 ml, transfusion
in a typical surgery would result in administration of a DEHP dose of
0.5 mg/kg/day.

**2.1.5 Cardiopulmonary bypass and ECMO**

Cardiopulmonary bypass is used in a number of cardiac surgical
procedures (e.g., heart valve replacement, CABG surgery, heart
transplantation, correction of congenital defects) and is also used as a
means to oxygenate the blood during cardiac or pulmonary failure.
Cardiopulmonary bypass used as a means to supplement blood oxygenation
is termed extracorporeal membrane oxygenation (ECMO). Since considerable
lengths of PVC tubing is typically used in heart-lung bypass circuits
(i.e., 600 cm of PVC tubing can be used in ECMO circuits) the potential
exists for patients undergoing these procedures to be exposed to DEHP.

Barry et al. (1989) showed that levels of DEHP and MEHP increased
dramatically in patients who had undergone cardiopulmonary bypass during
cardiac surgery. Although the dose of DEHP or MEHP received by these
patients only from the CPB device and PVC tubing was not calculated, the
total dose of these phthalate esters from all sources (i.e., tubing,
transfusions) was estimated (Table 2-5).

Table 2-5. Dose of DEHP received during cardiac surgery (Barry et al.,
1989)

+-----------------------------------+-----------------+-----------------+
| Procedure                         | DEHP dose       | MEHP dose       |
|                                   |                 | (mg/day)^1^     |
|                                   | (mg/day)^1^     |                 |
+-----------------------------------+-----------------+-----------------+
|                                   |                 |                 |
+-----------------------------------+-----------------+-----------------+
| Coronary artery bypass graft      | 15.4 to 72.9    | 2.2 to 8.0      |
| (CABG)                            |                 |                 |
+-----------------------------------+-----------------+-----------------+
| Orthotopic heart transplantation  | 2.3 to 21       | 0.45 to 2.5     |
+-----------------------------------+-----------------+-----------------+
| Artificial heart transplantation  | 3.8 to 167.9    | 0.25 to 18.8    |
+-----------------------------------+-----------------+-----------------+
|                                   |                 |                 |
+-----------------------------------+-----------------+-----------------+

^1^in the first 24 hours following surgery

Two groups of investigators, Shneider et al. (1989) and Karle et al
(1997), have estimated the dose of DEHP received by infants undergoing
ECMO (Table 2-6).

##### Table 2-6. Dose of DEHP received by infants undergoing ECMO

+-----------------------+-----------------------+-----------------------+
| **DEHP dose range**   | **DEHP concentration  | **Study**             |
|                       | in blood during ECMO  |                       |
| **(mg/kg)**           | (μg/ml)**             |                       |
+-----------------------+-----------------------+-----------------------+
|                       |                       |                       |
+-----------------------+-----------------------+-----------------------+
| 4.7 to 34.9           | 0 to 34.9^1^          | Karle et al. (1997)   |
+-----------------------+-----------------------+-----------------------+
|                       |                       |                       |
+-----------------------+-----------------------+-----------------------+
| 42 to 140^2^          | 26.8^3^               | Shneider et al.       |
|                       |                       | (1989)                |
|                       | 33.5^4^               |                       |
+-----------------------+-----------------------+-----------------------+
|                       |                       |                       |
+-----------------------+-----------------------+-----------------------+

^1^Depending on circuit, normalized to a 4 kg infant

^2^3 to 10 day course of treatment

^3^Following 14 days of ECMO

^4^Following 24 days of ECMO

Information is unavailable to accurately estimate the dose of DEHP
received by these patients on a mg/kg/day basis, since the exposure
period is represented as a range (3-10 days). However, if we assume that
the larger DEHP doses were received by patients undergoing this
procedure for 10 days, the time averaged dose of DEHP received by these
neonates is expected to be 3.5 to 14 mg/kg/day.

Estimates of DEHP dose derived by Karle et al. (1997) are based on the
rate at which DEHP is extracted from ECMO tubing by circulating blood
*in vitro*. It is interesting to note that Karle et al. (1997)
demonstrated that little or no DEHP was released from heparinized PVC
tubing. Although data are not available on the dose of DEHP received by
patients undergoing ECMO using a heparin-coated circuit, it is
anticipated, based on the results of the Karle et al. (1997) study, that
many patients currently undergoing this procedure will receive little or
no DEHP from the ECMO tubing. Although heparin-coated tubing is
available in the US, the FDA has not approved the use of heparinized
ECMO circuits.

Based on the data collected by Roy et al (2000), it is assumed that
fewer than 1000 infants undergo this procedure annually in the US.

# 2.1.6 Hemodialysis 

Hemodialysis represents a medical procedure that has the potential to
deliver considerable doses of DEHP to a patient. For example, Faouzi et
al. (1999b) recently reported that, on average, 75.2 mg of DEHP was
extracted during a single dialysis session, with a range of 44.3 to
197.1 mg. However, Faouzi et al. (1999b) pointed out that not all
infused DEHP is retained by the patient. These investigators have
estimated that 3.6 to 59.6 mg of DEHP is retained in a single dialysis
session. Assuming 3 dialysis sessions per week, this dose is equivalent
to a time-averaged dose of 0.02 to 0.36 mg/kg/day for a 70 kg patient.

##### 2.1.7 Peritoneal dialysis

Since peritoneal dialysis fluids are crystalloid in nature, it is not
surprising that little DEHP is delivered to a patient in this procedure.
Nassburger et al. (1987) measured levels of DEHP in peritoneal dialysis
solution ranging from 4 to 11 μg/L. Similarly, DEHP concentrations in
peritoneal dialysis fluid ranged from 1.1 to 3.7 μg/L, as measured by
Sugimura et al. (2001). However, Mettang et al. (1996) found DEHP levels
in dialysis fluid that ranged from 21 to 130 μg/L. Assuming a patient
undergoing continuous ambulatory peritoneal dialysis (CAPD) is dialyzed
with 8 L of fluid/day, the upper-bound estimate of the daily dose of
DEHP infused into the peritoneum would be on the order of 1 mg/day (0.13
μg/ml x 8,000 ml/day x 0.001 mg/μg). Since the majority of an
intraperitoneally injected dose of DEHP is not be absorbed (Rhodes et
al., 1983) the administered dose of 1 mg/day is likely to overestimate
the absorbed dose. Furthermore, a considerable amount of the infused
DEHP will be returned upon drainage of the perfusate from the
peritoneum.

Although the dose of DEHP or MEHP absorbed across the peritoneum by
patients undergoing CAPD is likely to be low, as compared to other
procedures, the endpoint of concern in patients exposed to DEHP and MEHP
from CAPD may be a "local" one - peritoneal sclerosis - an endpoint that
is not affected by the systemically absorbed dose. This issues is
discussed in more detail in Section 3.0.

**2.1.8 Apheresis**

Data are unavailable on the dose of DEHP received by donors undergoing
apheresis. However, Doull et al. (1999) used two assumptions to derive
an estimate of the DEHP dose received by individuals undergoing this
procedure: 1) that data on the amount of DEHP released during
hemodialysis provide an upper-bound estimate of DEHP dose for this
procedure and 2) that leaching of DEHP from PVC apheresis tubing is
linear over time. If 74 mg of DEHP are released during a hemodialysis
procedure lasting 5 hours (a value consistent with that reported by
Fauozi et al. 1999b), it was assumed by Doull et al. (1999) that 14.8 mg
of DEHP could be released during one apheresis procedure lasting one
hour. Further assuming that platelet/plasma donation occurs once/month,
the time averaged dose of DEHP received by a donor would be around 0.5
mg/day. FDA regulations stipulate that patients cannot donate platelets
more than twice per month. Also, 2 hours is a more realistic estimate
for the duration of an apheresis procedure. Therefore, assuming the dose
of DEHP received by an apheresis donor is probably more on the order of
1.97 mg/day. This dose is equivalent to 0.03 mg/kg/day for a 70 kg
donor; however, it should be pointed out that there is considerable
uncertainty associated with this estimate.

2.  **Oral Exposure**

In the medical device context, oral exposure to DEHP can occur following
release of this phthalate from enteral feeding bags and tubing or from
nasogastric tubing used for aspiration of stomach contents and
decompression of the stomach. An additional source of oral exposure to
phthalate esters, release from denture material, is possible. Although
DEHP has been detected in leachates from dental composites (Lee et al.,
1998), phthalates other than DEHP are typically used as plasticizers for
this application.

**2.2.1 Enteral feeding**

Enteral feeding is preferred over parenteral nutrition as a means to
provide nutrition to critically ill patients (Sigurdsson, 1997). Some
patients, especially those receiving care at home or in nursing
facilities, will receive nutritional support enterally (via the
gastrointestinal tract) rather than parenterally. Exposure to DEHP can
come from the PVC bag used to store the enteral nutrition solution and
the nasogastric tube, if one is used to administer the solution.

No data are available on the extent to which DEHP is released from
enteral nutrition storage bags; however, the assumption can be made that
these bags release DEHP at the same rate as bags used to store TPN
admixtures. The total amount of DEHP received by a patient receiving
enteral nutrition can be estimated from is the sum of the amount
released from the bag and from the tubing. Using the data from Mazur et
al. (1989), and assuming that that the enteral nutrition admixture
contains a similar amount of lipid as the parenteral admixture, an
upper-bound estimate of this dose is 9.47 mg/day, or 0.14 mg/kg/day. A
more typical daily dose from enteral nutrition would probably be on the
order of 0.04 mg/kg/day. By comparison, estimates of the amount of DEHP
received by the general population via food range from around 0.3 mg/day
for typical individuals to around 2 mg/day for highly exposed
individuals.

2.  **Breast milk**

One means of exposure to DEHP and MEHP that seems to have been largely
overlooked is lactational transfer from a nursing mother to her
offspring. The rodent studies that demonstrate adverse effects in
offspring following ingestion of milk from DEHP-exposed dams (e.g.,
Parmar et al, 1985; Dabholkar, 1988; Cimini et al., 1994; Stefanini et
al., 1997) suggest that transfer of enough DEHP or MEHP can take place
to cause adverse effects.

Some data are available on levels of DEHP in milk from healthy mothers
and KEMI (2000) has estimated that the average daily intake of DEHP via
nursing would be 0.021 mg/kg/day for infants aged 0-3 months and 0.008
mg/kg/day for 3- to 12- month-old children. However, experimental data
are unavailable on levels of DEHP in milk from mothers who have
undergone or are undergoing medical procedures such as hemodialysis. In
the absence of data from these patients, it's possible to derive
preliminary estimates the concentration of DEHP and MEHP in human milk
from levels of DEHP in the plasma or patients undergoing hemodialysis
and experimentally derived milk:plasma partition coefficients for rats
reported by Dostal et al. (1987) or by using theoretical partitioning
models, such as those developed by Begg and Atkinson (1993). Using
either of these approaches, it is possible to estimate that the dose of
DEHP received by nursing infants of mothers exposed to DEHP via
hemodialysis could be as much as 90 mg/kg/day (see Annex A for more
detail); however this value is highly uncertain. Because of the level of
uncertainty in this estimate, a TI/Dose ratio will not be derived for
this means of exposure to DEHP.

Bags used to store breast milk following the use of a breast pump are
typically made from polyethylene or nylon coated with polyethylene. In
addition, the expressed milk is not expected to come into contact with
flexible PVC components of the breast pump. Consequently, it is not
expected that infants will be exposed to any DEHP released from a breast
pump or milk storage bags.

3.  **Inhalation Exposure**

Since PVC tubing is used in respirators, it is theoretically possible
for some amount of this plasticizer to be released from the tubing into
the respiratory air stream and result in patient exposure. Based on the
concentration of DEHP measured in the air stream passed through PVC
respiratory tubing, Hill (1997) it is estimated that a patient
undergoing respiratory therapy would receive a daily DEHP dose ranging
from 28.4 to 94.6 μg, which is equivalent to a dose of 0.0004 to 0.001
mg/kg/day for a 70 kg adult.

**2.4 Dermal/Mucosal Exposure**

The potential exists for DEHP to be released from skin surface- or
mucosal membrane-contacting PVC devices such as urinary catheters, drug
delivery patches, occlusive dressings, oxygen masks, and endotracheal
tubes. However, there are insufficient data to accurately characterize
the amount of DEHP that would be released from these devices and taken
up by the body. Although nasogastric tubes contact the esophageal
mucosa, it is assumed that the majority of the DEHP released from these
devices is extracted from the lumenal side of the tubing and is
subsequently absorbed in the gastrointestinal tract.

Patients are assumed to have only incidental contact with PVC gloves
worn by health care workers. Since this safety assessment deals only
with potential health risks to patients, the potential risk to health
care workers from dermal exposure to DEHP will not be assessed. However,
it is useful to note that KEMI (2000) has estimated that a health care
worker wearing gloves for 2 hours/day could receive a DEHP dose of 0.007
mg/kg/day.

**2.5 Aggregate Exposure to DEHP from Multiple Medical Devices**

In additional to estimating exposure to DEHP on a procedure-by-procedure
basis, it is important to estimate the total or aggregate dose of DEHP
received by patients following exposure to multiple PVC devices.

**2.5.1 Neonates in NICU setting**

Neonates in the NICU environment are exposed to DEHP from multiple
devices. Based on the dose of DEHP received in such procedures as
intravenous administration of sedatives, administration of TPN and
replacement transfusion, all common procedures in the NICU, it is
possible to estimate that a 4 kg infant could receive a DEHP dose on the
order of 3 mg/kg/day for a periods of weeks or months (Table 2-7).

**Table 2-7. Aggregate exposure of neonates to DEHP in the NICU
environment.**

  ----------------------------------- -----------------------------------
  **Procedure**                       **DEHP dose (mg/kg/day)^1^**

  IV administration of sedative       0.03

  IV administration of TPN            2.5

  Replacement transfusion             0.3

  Total^2^                            2.83
  ----------------------------------- -----------------------------------

^1^4 kg infant

^2^Doesn't include DEHP does from endotracheal intubation, nasogastric
tube or ECMO

**2.5.2 Adult patients undergoing ECMO**

The total dose of DEHP received by patients undergoing ECMO can be
grossly underestimated if this dose is estimated simply from data on the
extent to which DEHP is released from PVC tubing used in the device.
Since these patients are multiply transfused and can receive over 600
transfused units (RBCs, platelet concentrates, FFP, cryoprecipitate)
during their course of ECMO and hospitalization, a considerable amount
of DEHP can also be received from transfused blood products as well as
the PVC used in the ECMO device. Patients undergoing ECMO are also
multiply transfused and may receive drugs (e.g., antibiotics, vitamins)
solubilized in pharmaceutical surfactants that promote DEHP release from
PVC bags. For example, an adult undergoing ECMO could receive a DEHP
dose ≥ 4 mg/kg/day, if aggregate exposure from multiple devices is
considered. The principle contribution to the total dose of DEHP
received by these patients comes from the multiple transfusions needed
by these patients, not the PVC tubing used in the ECMO device.

**2.5.3 Adult patients undergoing surgical procedures**

Adult patients receiving a coronary artery bypass graft surgery are can
receive DEHP from a during a number of medical devices, including an
endotracheal tube, IV bags and tubing (especially if a multivitamin
solution is infused), chest tubes, hemodynamic monitoring catheters,
nasal cannula, nasogastric tube, and blood bags and administration sets.
The dose of DEHP received by these patients, as estimated by Barry et
al. (1989), is based on the concentration of DEHP in the blood, and
therefore, takes into account aggregate exposure.

3.  **Derivation of Tolerable Intake (TI) Values**

The process used to derive the Tolerable Intake (TI) values for DEHP is
outlined in ISO/DIS 10993-17, *Method for the Establishment of Allowable
Limits for Leachable Substances*, and is illustrated in Figure 3-1.

**Figure 3-1. Process for Deriving Tolerable Intake (TI) Values (from
ISO/DIS 10993-17)**

### 

Briefly, this approach involves the following steps. Following a
comprehensive review of the literature, data from critical studies were
identified to serve as the basis for the selection of
no-observed-adverse-effect-level (NOAEL) and lowest observed adverse
effect-level (LOAEL) (Step 1). The complete database of studies reviewed
for the safety assessment is summarized in Annex B; however, the merits
and limitations of studies that reported the highest NOAELs and lowest
LOAELs following parenteral administration of DEHP to experimental
animals are reviewed in more detail in this section to illustrate how
the critical values were selected. Once the most appropriate NOAEL and
LOAEL values were selected, Uncertainty Factors (UFs) were derived to
account for: 1) variability in response in the human population, 2)
assumed differences in the potency of DEHP between experimental animals
and humans, and 3) various other limitations in the database (Step 2).
The NOAEL and LOAEL values selected from the critical studies were then
divided by the product of the UFs (known as the Modifying Factor) to
derive the TI (Step 3):

TI (mg/kg/day) = NOAEL or LOAEL (mg/kg/day)

Modifying Factor

### 

### Since the potency of DEHP differs across routes of exposure, separate TIs were derived for oral and parenteral exposure to the compound.

Although ISO/DIS 10993-17 instructs the user to derive a cancer-based TI
when appropriate, there is considerable uncertainty with regard to the
carcinogenic potential of DEHP in humans. Further, insufficient data
exist to derive a cancer-based TI for DEHP for parenteral routes of
exposure. As a result, a TI based on carcinogenicity will not be derived
at this time for DEHP. Also, the methodology described in ISO/DIS
10993-17 allows the user to derive an Allowable Limit (AL) value from
the TI value; however, derivation of an AL takes into account factors
such as technical and economic feasibility that are beyond the scope of
this safety assessment.

**3.1 Selection of Appropriate NOAEL and/or LOAEL Values from Critical
Studies (Step 1)**

Table 3-1 summarizes the results of studies in which the lowest
parenteral LOAEL values for DEHP were reported in the literature
(parenteral studies listed in ascending order according to LOAEL). The
reader should note that many studies other than those listed in Table
3-1 were reviewed in this safety assessment. The results of these
additional studies are summarized in Annex B. The criteria for
determining the applicability of these study results for derivation of
TI values for DEHP are summarized in Table 3-2.

# Table 3-1. Critical toxicity studies for DEHP

+-----------------+---------+----------+----------+-------------------+
| **Study**       | **      | *        | *        | **Effect(s) at    |
|                 | Route** | *NOAEL** | *LOAEL** | LOAEL**           |
|                 |         |          |          |                   |
|                 |         | **(mg/k  | **(mg/k  |                   |
|                 |         | g/day)** | g/day)** |                   |
+-----------------+---------+----------+----------+-------------------+
| Jacobson et al. | IV      |          | 0.021    | Histopathological |
| (1977)          |         |          |          | changes in liver, |
|                 |         |          |          | altered BSP       |
|                 |         |          |          | clearance         |
|                 |         |          |          | kinetics          |
+-----------------+---------+----------+----------+-------------------+
| Fracasso et al. | IP      |          | 0.05     | Peritonitis       |
| (1999)          |         |          |          |                   |
+-----------------+---------+----------+----------+-------------------+
| Nair et al.     | IP      |          | 0.75     | Reduced levels of |
| (1998)          |         |          |          | Vitamin E in the  |
|                 |         |          |          | liver             |
+-----------------+---------+----------+----------+-------------------+
| Miripol et al.  | IV      | 0.33     | 1.1      | Reduced uptake of |
| (1975)          |         |          |          | colloidal carbon  |
+-----------------+---------+----------+----------+-------------------+
| Komitowski et   | IP      |          | 4.3      | Morphological     |
| al. (1986)      |         |          |          | changes observed  |
|                 |         |          |          | in hepatocytes    |
|                 |         |          |          | using image       |
|                 |         |          |          | analysis          |
+-----------------+---------+----------+----------+-------------------+
| Petersen et al. | IV      |          | 5.0      | Reduced fertility |
| (1975)          |         |          |          |                   |
+-----------------+---------+----------+----------+-------------------+
| Rubin and Chang | IV      |          | 7.7 to   | Pulmonary effects |
| (1978)          |         |          | 13       |                   |
+-----------------+---------+----------+----------+-------------------+
| Rutter (1973)   | IV      |          | 21.4     | Hepatomegaly,     |
|                 |         |          |          | increased liver   |
|                 |         |          |          | enzyme levels,    |
|                 |         |          |          | increased lung    |
|                 |         |          |          | weight            |
+-----------------+---------+----------+----------+-------------------+
| Rubin and Chang | IV      |          | 40       | Reduced blood     |
| (1976)          |         |          |          | pressure          |
+-----------------+---------+----------+----------+-------------------+
| Curto and       | IP      |          | 50       | Reduced           |
| Thomas (1982)   |         |          |          | testicular Zn     |
+-----------------+---------+----------+----------+-------------------+
| Petersen (1975) | IV      |          | 50       | Reduced litter    |
|                 |         |          |          | size following    |
|                 |         |          |          | exposure of       |
|                 |         |          |          | treated males to  |
|                 |         |          |          | untreated females |
+-----------------+---------+----------+----------+-------------------+
| Greener et al.  | IV      | 92       | 165      | Reduced body      |
| (1987)          |         |          |          | weight gain,      |
|                 |         |          |          | hepatomegaly,     |
|                 |         |          |          | ↑SGOT             |
+-----------------+---------+----------+----------+-------------------+
| Sjoberg et al.  | IV      | 25       | 250      | Altered Sertoli   |
| (1985a)         |         |          |          | cells,            |
|                 |         |          |          | degeneration of   |
|                 |         |          |          | primary           |
|                 |         |          |          | spermatocytes     |
+-----------------+---------+----------+----------+-------------------+
| Baxter et al.   | IV      | 60       |          | No adverse        |
| (2000)          |         |          |          | effects           |
+-----------------+---------+----------+----------+-------------------+
| AdvaMed (2001)  | IV      | 60       | 300      | Testicular        |
|                 |         |          |          | atrophy, decrease |
|                 |         |          |          | in diameter of    |
|                 |         |          |          | seminiferous      |
|                 |         |          |          | tubules and       |
|                 |         |          |          | depletion of      |
|                 |         |          |          | germinal cells in |
|                 |         |          |          | testes,           |
|                 |         |          |          | hepatomegaly      |
+-----------------+---------+----------+----------+-------------------+

# 

# 

# 

# 

# 

# Table 3-2. Criteria to Determine Appropriateness of Study for TI Derivation

  ----------------------------------- -----------------------------------
  **Criteria**                        **Explanation**

  Relevance of the effect for humans  Hepatomegaly and other liver
                                      effects produced by DEHP in mice
                                      after oral (and presumably
                                      parenteral) administration have
                                      been shown to be mediated by PPARα
                                      in this species (Ward et al.,
                                      1998). Since humans are thought to
                                      be relatively refractory to the
                                      hepatic effects mediated by PPARα
                                      (Cattley et al., 1998; Roberts,
                                      1999), studies reporting this
                                      endpoint were not used as the basis
                                      for TI derivation. In contrast,
                                      there is no mechanistic reason to
                                      believe that reproductive effects
                                      seen in DEHP-exposed rodents are
                                      not relevant for humans.

  Dosage form of DEHP used            Neat (undiluted) DEHP is fairly
                                      viscous at room temperature.
                                      Consequently, when neat DEHP is
                                      injected intravenously, it may
                                      produce effects in "filtering"
                                      organs such as the lungs and liver
                                      by occluding capillary flow and not
                                      because of the intrinsic toxicity
                                      of the compound. As a result,
                                      studies in which DEHP was injected
                                      neat will not serve the basis of TI
                                      values for this compound.

  Relevant routes of exposure         Since DEHP is converted to MEHP by
                                      lipase in the gastrointestinal
                                      tract, it is more potent when given
                                      orally than by parenteral routes of
                                      exposure. Therefore, studies in
                                      which DEHP was administered orally
                                      will not serve as the basis for
                                      parenteral TI values.

  Effects should be considered to be  Many of the effects described in
  adverse                             Table 3-1 (e.g., changes in enzyme
                                      or antioxidant levels) are not
                                      typically considered to be
                                      "adverse" from a risk assessment
                                      perspective, but rather, are
                                      considered to be "subclinical" or
                                      "precursor" effects. Only studies
                                      with effects broadly considered to
                                      be adverse (histopathological or
                                      functional changes) will serve as
                                      the basis for TI derivation.

  Publication form                    Insufficient detail is provided in
                                      studies reported only in abstract
                                      form to evaluate their usefulness
                                      for TI derivation.
  ----------------------------------- -----------------------------------

The rationale for accepting or rejecting each of the studies listed in
Table 3-1 as the basis for the TI values for DEHP is explored below.

***Jacobson et al. (1977)***

Jacobson et al. (1977) reported that monkeys repeatedly infused (weekly
for one year) with platelet-rich plasma (PRP) stored in PVC blood bags
for 48 hours had impaired liver function and abnormal liver
histopathology upon completion of the transfusions. The mean dose of
DEHP received by two monkeys receiving PRP stored at 4^o^ C for one year
was 0.021 mg/kg/day; the mean dose in three monkeys receiving PRP stored
at 22^o^ C was 0.073 mg/kg/day. There are several factors that suggest
that this study is relevant and appropriate for the development of the
TI derivation. These factors include:

-   use of a clinically relevant route and duration of exposure,

-   manifestation of these effects in a primate model, not simply a
    rodent species,

-   a clinically relevant means of introducing the DEHP into PRP
    (leaching from the PVC bag, not solubilization in a detergent),

-   the finding that multiple, divergent, and clinically relevant
    hepatic endpoints (e.g.,

-   BSP clearance, histopathology) are affected, and

-   Since the study employed plasma instead of blood, there is no need
    to account adverse hepatic effects that could be caused by hemolysis
    of stored blood.

Despite these factors, the relevance of the findings of the Jacobson et
al. (1977) study has been challenged by several groups, notably, Baxter
(1999), HIMA (1999) and the authors of the Koop report (Koop et al.,
1999). For example, the Baxter (1999) scientists point out:

-   The authors (Jacobson and colleagues) conceded that the observed
    effects are mild and could be attributed to background effects.

-   The study showed no change in standard liver function.

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-   A valid statistical analysis of the results was not performed
    because of the small number of animals used in the study.

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-   No liver pathology was evident in the animal with the highest
    hepatic levels of DEHP.

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-   Factors other than DEHP exposure, specifically, infection of the
    monkeys with tuberculosis and the possible reaction of the monkeys
    to foreign protein in the infused blood components from other
    monkeys, could be responsible for the effects seen.

Although effects in the liver of monkeys were seen at very low doses of
DEHP in the study of Jacobson et al. (1977), there is considerable
controversy about the relevance of these findings. As a result, the
results of the study by Jacobson et al. (1977) will not be used at this
time for the derivation of TI values for DEHP. This decision is
consistent with that reached by other regulatory agencies (e.g.
CalEPA/OEHHA) and advisory panels (CERHR, 2000).

***Fracasso et al. (1999)***

A recent study (Fracasso et al., 1999) demonstrated that peritoneal
sclerosis was produced in rats following intraperitoneal injection of a
DEHP dose of 0.05 mg/kg/day for 7 days. However, peritoneal sclerosis
represents a "local" effect, not a systemic one. Therefore, the results
of the Fracasso et al. (1999) study will not be used for the derivation
of a TI based on systemic effects. In addition, DEHP was injected neat
in the Fracasso et al. (1999) study, calling into question the relevance
of the results for the clinical situation.

***Miripol et al. (1975)***

Miripol et al. (1975) found no difference in the rate at which carbon
particles were cleared from the blood of rats administered
DEHP-containing PVC extracts for 26 days; however, a reduced clearance
rate was observed in rats that had received DEHP-containing PVC extracts
at a dose of 1.1 mg/kg/day for 63 days (19 injections of plasma
containing 3.7 mg DEHP/kg BW). This subtle effect is not typically
considered to be "adverse" for the purpose of TI derivation.

***Komitowski et al. (1986)***

Subtle morphological changes were seen in hepatocytes using image
analysis following a single IP injection of DEHP at a dose of 30 mg/kg,
with sacrifice 7 days later (Komitowski et al., 1986). The time-averaged
dose of DEHP in this study is equivalent to 4.3 mg/kg/day. Morphological
changes seen using image analysis represent a subtle alteration that
would not normally be considered to be adverse. Since no effects were
seen in a more traditional histopathological examination of the tissue,
the results of this study will not serve as the basis for TI
derivations.

***Petersen et al. (1975)***

Although Petersen et al. (1975) reported reduced fertility in mice
following IV injection of DEHP, some uncertainty exists about the actual
doses that were used in the study. For example, Petersen et al. (1975)
state: "Three levels 5 mg, 25 mg, and 50 mg per 100 cc of serum were
used". If this concentration was correct, it would require
administration of approximately 30 ml of serum to a rat to achieve the
stated doses. This is obviously a physical impossibility.

# *Rubin and Chang (1976, 1978)*

Rubin and Chang (1976) measured a fall in arterial blood pressure of 45
mm Hg following intravenous administration of a 40 mg/kg dose of DEHP to
rats. However, the DEHP was solubilized in Tween 80, raising some
concerns about the potentiating effect of the vehicle. In addition, the
results were only published in abstract form. As a result, they will not
be used for derivation of a TI for DEHP.

A LOAEL of 7.7 to 13 mg/kg was reported by Rubin and Chang (1978) for
adverse pulmonary effects following intravenous administration of DEHP
to rats that had undergone a period of hypovolemia followed by
re-transfusion of blood. These results suggest that the injured lung may
be more susceptible than a healthy lung to adverse effects produced by
intravenous administration of DEHP. Although concerns about the physical
effects of DEHP are minimized by the use of plasma-solubilized DEHP in
this study, they cannot be completely dismissed. Also, since the data
were only reported in abstract form, these results will not be used as
the basis for TI derivation. However, the ability of hypovolemia with
reperfusion to potentially increase the pulmonary toxicity of
intravenously administered DEHP is intriguing and deserves further
study.

***Rutter (1973)***

Changes in liver weight and hepatic enzyme levels were observed in dogs
following intravenous administration of DEHP for 4 weeks. The following
factors support the selection of this dose as the LOAEL upon which a TI
value can be derived:

-   The effects are seen in a non-rodent species, minimizing concerns
    about the relevance of these findings for humans.

-   The study employs a clinically relevant route of exposure. Use of
    the intravenous route of administration also minimizes uncertainty
    about the extent to which the administered dose was absorbed.

-   The endpoints observed (hepatomegaly, altered liver enzymes) are
    consistent with those seen in other studies following exposure of
    experimental animals to DEHP and in patients undergoing
    hemodialysis.

-   The presence of both morphological and biochemical changes
    strengthen the conclusion that adverse hepatic effects are
    occurring, compared to the presence of only one of these effects.

-   The changes seen in liver weight and alkaline phosphatase levels are
    dose-dependent.

However, there are concerns about the use of these results for
establishing TI values for DEHP, notably, that the DEHP was administered
neat, that a small number of dogs was used in each experimental group
and that the study was unpublished.

***Curto and Thomas (1982)***

Decreased levels of prostatic and testicular zinc were observed by Curto
and Thomas (1982) following intraperitoneal injection of rats with 100
mg/kg DEHP every other day for 20 days (50 mg/kg/day). Similar effects
were not seen in mice exposed to the same dose of DEHP for 20 days, nor
in mice or rats injected intraperitoneally with DEHP at doses of 50 or
100 mg/kg/day for 5 consecutive days. Histopathological examination of
the tissues was apparently not carried out in this study. Since 100
mg/kg was the lowest dose administered in the 20-day study, a NOAEL for
this effect was not identified.

Reduction in prostatic and testicular zinc levels is a hallmark of DEHP
exposure. However, changes in enzyme activity in a tissue or
concentrations of a cellular constituent do not represent an "adverse"
event that should serve as the basis for a LOAEL. For example, the EPA
(1996) [Reproductive Toxicity Risk Assessment Guidelines]{.underline}
instruct the user to consider biochemical evidence in a supporting
fashion. The guidelines note:

> The LOAEL is the lowest dose at which there is a significant increase
> in the frequency of adverse reproductive effects compared with the
> appropriate control group in a database having sufficient evidence. A
> significant increase may be based on statistical significance or on a
> biologically significant trend. **Evidence for biological significance
> may be strengthened by mode of action or other biochemical evidence at
> lower exposure levels that supports the causation of such an effect**
> (emphasis added).

This statement implies that biochemical evidence itself should not serve
as the basis for a LOAEL determination, but rather, could be used to
provide mechanistic evidence for the effects that occur at higher doses.

The guidance provided by Moore et al. (1995) is more explicit with
regard to this issue.

> *Biochemical markers of reproductive exposure and effect*. Various
> markers of exposure and effect have been investigated in male
> reproductive toxicology, including prosatein, androgens, and prolactin
> (65). Sertoli cell enzymes or biochemical secretory products, measured
> *in vitro* and *in vivo* as markers of cell function, are other
> examples of useful end points for studying target organ or cell
> responses. **Currently, however, they cannot be considered evidence of
> male reproductive toxicity** (emphasis added)**.**

Nevertheless, there are various factors that support the conclusion that
altered zinc levels may at least represent a [precursor]{.underline}
effect in DEHP-exposed animals. For example,

-   Reduced testicular zinc has been observed in a number of studies
    (not just Curto and Thomas, 1982), in multiple animal species (not
    just rodents), and following administration of DEHP or MEHP via
    various routes of exposure.

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-   Dietary zinc deficiency is associated with infertility in
    experimental animals.

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-   Reduced levels of seminal zinc are associated with oligospermia in
    infertile men.

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-   DEHP is thought to exert its teratogenic effect in rodents via
    induction of metallothionein in the liver, with subsequent binding
    of plasma zinc. This sequence of events results in reduced levels of
    zinc in the fetus, a finding associated with developmental toxicity
    in offspring of exposed animals. It is reasonable to assume that a
    similar mechanism may serve as the basis for DEHP-associated
    testicular damage and infertility.

A zinc-deficient diet has been shown to produce a range of adverse
testicular effects in rats including, degeneration of seminiferous
tubules and interstitial tissue, necrosis of germ cell precursors,
spermatic arrest, and testicular atrophy (Hafiez et al.,1990; Hamdi et
al., 1997; Merker and Gunther, 1997) and levels of zinc in seminal fluid
have been shown to be lower in oligospermic men than in normospermic,
fertile men in some studies (e.g., Caldamone et al., 1979; Mohan et al.,
1997), but not others (e.g., Madding et al., 1986; Adejuwon et al.,
1996).

Zinc deficiency can increase the sensitivity of the testes to the toxic
effect of other agents, such as cadmium (Oteiza et al., 1999). Since
co-exposure of patients to DEHP and other testicular toxicants such as
ethylene oxide (Kaido et al., 1992) can occur in various clinical
scenarios (e.g., hemodialysis), the potential exists for DEHP to
potentiate the adverse testicular effects of other compounds via a
mechanism involving zinc depletion in the testes.

Mechanistically, reduced zinc could play a role in the etiology of
DEHP-induced testicular toxicity, either through a reduction of
angiotensin-converting enzyme activity (Rahman et al., 1999) or by
failure to inhibit superoxide dismutase (SOD) activity which could lead
to increased superoxide anion production (Gavella et al., 1999).

It is interesting to note that plasma (but not blood) concentrations of
zinc are reduced in men undergoing hemodialysis. These patients are not
only exposed to relatively high levels of DEHP, but also experience a
high incidence of testicular atrophy and infertility. Therefore, the
effects seen in rodents may have a clinical correlate in humans.

Despite these factors, it is appropriate to consider an endpoint such as
altered zinc in the testes of DEHP-exposed animals to be a precursor
event to more serious effects; however, it should not be considered to
be an adverse effect in its own right for the derivation of a TI value.

***Greener et al. (1987)***

Greener et al. (1987) investigated the toxicity of DEHP administered
intravenously to 3-day-old rat pups for 18 consecutive days at doses of
30.8, 91.7, or 164.8 mg/kg/day. A significant (*p* \< 0.01)
dose-dependent decrease in body weight gain and average weight gain per
day was observed in DEHP-treated animals relative to controls. However,
the body weight data in the Greener et al. (1987) paper were reported in
bar graph form, not in a tabular format, so it is impossible to
determine if there is a statistically significant difference in body
weight between controls and any individual treatment group.
Nevertheless, based on observation of the Figure 2 in the Greener et al.
(1987) paper, it appears that mean (presumably) body weights of animals
in the 30.8 mg/kg/day exposure group did not differ from those in the
BSA control group. The difference in body weight may have reached
statistical significance in the group administered DEHP at a dose of
164.8 mg/kg/day, as compared to BSA-injected controls. In addition to
changes in body weight, there was a dose-dependent increase in absolute
and relative liver weight in DEHP-exposed rat pups that reached
statistical significance in the high dose (164.8 mg/kg/day) group. No
adverse histological effects were noted in any organ examined (brain,
heart, lungs, liver, spleen, kidneys, eyes, stomach, duodenum, and
caecum), with the exception of injection site lesions, at any dose used
in the Greener et al. (1987) study.

***Sjoberg et al. (1985a)***

Although no change in testicular weight was observed in rats
administered DEHP intravenously every other day for 10 days,
histopathological changes were seen in the testes of rats exposed to the
highest dose of DEHP used in this study, 500 mg/kg or 250 mg/kg/day
(Sjoberg et al., 1985a). The histopathological effects, including
Sertoli cells vacuolization and some spermatocyte degeneration, were
only observed in Epon-embedded testicular tissue, not tissue embedded in
paraffin. Further, these effects were observed only following electron
microscopy examination of the tissues and were not evident following
examination with light microscopy. The NOAEL in this study was 50 mg/kg
or 25 mg/kg/day on a time-averaged basis.

Since the study employed a clinically relevant route of exposure; is
based on an endpoint assumed to be relevant for humans; involved
injection of solubilized (not neat) DEHP; utilized multiple dose levels,
appropriate controls and rigorous histopathological examination of the
tissues; and detected an endpoint considered to be adverse, the results
of the Sjoberg et al. (1985a) study will be used for the derivation of
TI values for DEHP. Since the effects seen at the 250 mg/kg/day dose are
subtle, the "true" NOAEL for this study is probably closer to 250
mg/kg/day than 25 mg/kg/day. However, rats in this study were 40 days
old. It is possible that a higher NOAEL/lower LOAEL would have been
detected if neonatal animals were used in the study.

***Baxter (2000)***

The Baxter Healthcare Corporation (Baxter, 2000) recently made public
the results of an unpublished study in which neonatal male rats or
rabbits were injected either with DEHP or 4% bovine serum albumin during
postnatal days 3-21 (rats) or 14-42 (rabbits). Histopathological
examination of the testes and other organs of DEHP-exposed animals
revealed no histologic alterations that could be attributed to the test
material administered at a dose of 62 mg/kg/day.

***AdvaMed (2001)***

AdvaMed (2001) recently made available the results of a 21-day repeat
dose study of DEHP in neonatal (3- to 5-day old) rats to the FDA. A
second group of animals was dosed for 21 days, then held for a recovery
period until 90 days of age. At the end of the 21-day dosing period,
testicular atrophy and hepatomegaly were observed in neonatal rats
following daily intravenous exposure to DEHP at a dose of 300 mg/kg/day.
Histopathological examination of the testes of animals in the 300
mg/kg/day dosing group revealed a decrease in the diameter of the
seminiferous tubules and a mild depletion of germinal epithelial cells.
Although testicular atrophy persisted at the end of the recovery period,
histopathological changes were not seen in the recovery group previously
exposed to a DEHP dose of 300 mg/kg/day for 21 days. The NOAEL in the
study was 60 mg/kg/day; consistent with the results reported previously
by Baxter (2000).

In addition to investigating organ weight changes and conducting a
histopathological examination of tissues, AdvaMed (2001) also performed
a functional assessment of male reproductive capacity (sperm count,
sperm motility and sperm morphology) in DEHP-exposed rats at the end of
the recovery period. No effect on any of these parameters was observed
in the recovery group of animals.

The considerations discussed above regarding the relevance of these
studies for TI derivation are summarized in Table 3-3.

# Table 3-3. Evaluation of critical toxicity studies (parental route) for DEHP

  --------------- ----------- ------------------- -------------- --------------------
  **Study**       **Route**   **Effect(s) at      **Accept or    **Rationale**
                              LOAEL**             Reject Study   
                                                  for TI         
                                                  Derivation**   

  Jacobson et al. IV          Histopathological   Reject         Questions about role
  (1977)                      changes in liver,                  of confounding
                              altered BSP                        factors (e.g., TB
                              clearance kinetics                 outbreak)

  Fracasso et al. IP          Peritonitis         Reject         Local effect
  (1999)                                                         

  Nair et al.     IP          Reduced levels of   Reject         Not considered to be
  (1998)                      Vitamin E in the                   an adverse effect
                              liver                              

  Miripol et al.  IV          Reduced uptake of   Reject         Not considered to be
  (1975)                      colloidal carbon                   an adverse effect

  Komitowski et   IP          Morphological       Reject         Not considered to be
  al. (1986)                  changes observed in                an adverse effect
                              hepatocytes using                  
                              image analysis                     

  Petersen et al. IV          Reduced fertility   Reject         Questions about dose
  (1975)                                                         

  Rubin and Chang IV          Pulmonary effects   Reject         Questions about
  (1978)                                                         dose; only published
                                                                 in abstract form

  Rutter (1973)   IV          Hepatomegaly,       Reject         Questions about role
                              increased liver                    of confounding
                              enzyme levels,                     factors (DEHP
                              increased lung                     administered neat)
                              weight                             

  Rubin and Chang IV          Reduced blood       Reject         Only published in
  (1976)                      pressure                           abstract form

  Curto and       IP          Reduced testicular  Reject         Not considered to be
  Thomas (1982)               Zn                                 an adverse effect

  Petersen (1975) IV          Reduced litter size Reject         Questions about dose
                              following exposure                 
                              of treated males to                
                              untreated females                  

  Greener et al.  IV          Reduced body weight Reject         Questions about the
  (1987)                      gain, hepatomegaly,                way data were
                              ↑SGOT                              presented and
                                                                 statistical
                                                                 significance of
                                                                 differences. Liver
                                                                 effects assumed to
                                                                 be not relevant for
                                                                 humans

  Sjoberg et al.  IV          Altered Sertoli     Accept         Appropriate for use
  (1985a)                     cells, degeneration                
                              of primary                         
                              spermatocytes                      

  Baxter (2000)   IV          No adverse effects  Accept         Appropriate for use

  AdvaMed (2001)  IV          Testicular atrophy, Accept         Appropriate for use
                              decrease in                        
                              diameter of                        
                              seminiferous                       
                              tubules and                        
                              depletion of                       
                              germinal cells in                  
                              testes,                            
                              hepatomegaly                       
  --------------- ----------- ------------------- -------------- --------------------

Based on these considerations, the parenteral TI values for DEHP will be
based on the NOAEL from the Baxter (2000) and AdvaMed (2001) studies and
the LOAEL from the Sjoberg et al. (1985a) study.

Since the toxicity of DEHP following oral administration has been
adequately reviewed in other risk assessments (e.g., ATSDR, 2000; CERHR,
2000; KEMI, 2000), no attempt has been made to do so here. The highest
NOAEL/lowest LOAEL reported in a valid study for DEHP are 5.8 and 28.9
mg/kg/day, as reported by David et al. (2000). The NOAEL and LOAEL
values are consistent with those reported by Poon et al. (1997). Since
there is some question about whether the effects seen at this dose in
the David et al. (2000) study are dose-related, age-related, or a
combination of both, they will not be used as the basis for TI
derivation for DEHP. However, the effects seen in the Poon et al. (1997)
study are unambiguous and the NOAEL and LOAEL values are essentially the
same as those in the David et al. (2000) study, therefore, the oral TI
for DEHP will be derived using the NOAEL from the Poon et al. (1997)
study.

# 3.2 Derivation of a Modifying Factor (Step 2)

As defined in ISO/DIS 10993-17, a modifying factor is the product of
uncertainty factors selected to account for interindividual variability
among humans, interspecies extrapolation, and various deficiencies in
the toxicological data available to derive a TI (e.g., lack of a NOAEL,
lack of data from appropriate routes or durations of exposure). The
value is unitless and is derived as follows:

Modifying factor = UF1 x UF2 x UF3,

where UF1, UF2, and UF3 are defined in Table 3-4.

# Table 3-4. Uncertainty Factors for TI Derivation

+-----------------------+----------+----------+-----------------------+
| **Uncertainty Factor  | ####     | **D      | **Description**       |
| Designation**         | ## Range | efault** |                       |
+-----------------------+----------+----------+-----------------------+
| UF1, Interindividual  | 1-10     | 10       | To account for the    |
| Variability in the    |          |          | variability in        |
| Human Population      |          |          | response between the  |
|                       |          |          | mean of the healthy   |
|                       |          |          | population and the    |
|                       |          |          | response in some      |
|                       |          |          | proportion of a       |
|                       |          |          | sensitive             |
|                       |          |          | subpopulation.        |
+-----------------------+----------+----------+-----------------------+
| UF2, Interspecies     | 1-10     | 10       | To account for the    |
| Extrapolation         |          |          | possibility that      |
|                       |          |          | humans are more       |
|                       |          |          | sensitive to the      |
|                       |          |          | adverse effects of a  |
|                       |          |          | compound than         |
|                       |          |          | experimental animals  |
|                       |          |          | are.                  |
+-----------------------+----------+----------+-----------------------+
| UF3, Quality and      | 1-100    | 1        | To account for        |
| Relevance of the      |          |          | limitations in the    |
| Experimental Data     |          |          | toxicological data    |
|                       |          |          | available for TI      |
|                       |          |          | derivation, including |
|                       |          |          | absence of NOAEL      |
|                       |          |          | value, absence of     |
|                       |          |          | NOAEL from a          |
|                       |          |          | long-term study, and  |
|                       |          |          | lack of data from a   |
|                       |          |          | clinically relevant   |
|                       |          |          | route of exposure.    |
+-----------------------+----------+----------+-----------------------+

Ideally, the process for selecting values for each of these uncertainty
factors is informed by experimental data on the variability in the human
response to a compound (UF1) and compound-specific differences in
potency between animals and humans (UF2). Some data are available to
determine whether the default values proposed for each of these UFs are
appropriate or whether an alternative value is justifiable, as discussed
below. Also, the conditions under which the experimental study is
conducted should be similar to those under which patients are exposed to
the compound. Since the conditions used in the Baxter (2000, 2001) and
Sjoberg et al. (1985a) studies do not exactly mimic the clinical
situation, an additional UF to account for data deficiencies (UF3) was
selected, as discussed below.

**3.2.1 Interindividual variability in the human population (UF1)**

An upper-bound default value of 10 is selected for UF1 to account for
the variability in pharmacokinetic behavior of DEHP in the general
population and the presumed increased sensitivity of neonates and
critically ill patients to the adverse effects of DEHP, compared to
adults and healthy individuals, respectively. The rationale for
selecting this value is discussed below.

**3.2.1.1 Pharmacokinetic variability in the general population and in
patients**

DEHP is converted to its active metabolite, MEHP, by lipase enzymes
(Albro and Thomas, 1973) and MEHP is eliminated following conjugation
with glucuronide (Sjoberg et al., 1991). Consequently, individuals with
high rates of lipase activity and/or low rates of glucuronidation
activity could be at higher risk of DEHP-induced adverse effects than
the rest of the population.

Polymorphisms in genes coding for pancreatic (Hegele et al., 2001) and
hepatic (Cohen et al., 1999) lipase in humans are known to exist and
these polymorphisms can result in lipase deficiency. Low lipase activity
would be expected to exert a protective effect in these individuals with
regard to DEHP-mediated effects. Conversely, pancreatic lipase activity
is increased by heparin administered to patients on hemodialysis
(Montalto et al., 1997) and plasma lipoprotein lipase activity is
increased by erythropoietin (Goto et al., 1999), which is also
administered to patients on hemodialysis. Increased lipase activity
would facilitate the conversion of DEHP to its active metabolite.
Smoking is also known to increase lipase activity (Kong et al., 2001)
and DEHP itself induces lipase activity in rodents (Mocchiutti and
Bernal, 1997). Consequently, some individuals in the DEHP-exposed
population can convert DEHP to MEHP more efficiently than others. This
variability is evidenced, to some extent, by the variability in the rate
at which intestinal mucosal cell preparations obtained from two humans
hydrolyzed a number of di-n-alkyl phthalates (Lake et al., 1977). The
metabolic rates between these two individuals differed by around 3- to
6-fold. Presumably, the degree of variability would increase with a
larger sample size.

Polymorphisms have been detected in several human
UDP-glucuronyltransferase (UGT) genes resulting in variability in UGT
activity in the human population (de Wildt et al., 1999). The
polymorphic expression of UGT may be responsible for the large
interindividual variation in the conjugation of MEHP in humans (Dirven
et al., 1993). Presumably, this variability will result in a reduced
capacity of some individuals to conjugate and eliminate MEHP. Reduced
ability to glucuronidate exogenous compounds can have clinical
consequences, since adverse drug reactions have been observed in
patients with deficient UGT activity (Burchell et al., 2000). In
addition, various disease states (e.g., cirrhosis) and drugs can impair
glucuronidation capacity (Furlan et al., 1999). It is interesting to
note that propofol can inhibit UGT activity (Chen et al., 2000) and as
discussed in Section 2.0, administration of propofol is also associated
with the release of considerable amounts of DEHP from PVC tubing (Loff
et al., 2000).

######## 3.2.1.2 Children as a High Risk Population

Based on the results of experimental animal studies, children may be
more susceptible than adults to the toxic effects of DEHP following oral
exposure; it's not clear whether age-related differences in DEHP-induced
testicular toxicity would occur following parenteral exposure.
Supporting this conclusion are data from Gray and Butterworth (1980),
Sjoberg et al. (1985a), and Dostal et al. (1988) showing that testicular
toxicity is produced following oral exposure of prepubertal rats to DEHP
at doses lower than those required to produce this effect in sexually
mature rats. However, no age-related differences in the expression of
testicular toxicity were seen following intravenous administration of
DEHP to rats (Sjoberg et al., 1985c). Nevertheless, there are various
factors that may result in increased sensitivity of children to DEHP,
compared to adults, even after IV exposure. For example, metabolic
differences between children and adults may place children at increased
risk of DEHP toxicity. Children have a reduced capacity to metabolize
compounds via glucuronidation, compared to adults. Since 60% of an
administered dose of DEHP is excreted in humans as the glucuronide
conjugate (Albro et al., 1982), a reduced glucuronidation capacity could
result in delayed excretion of DEHP or its metabolites. This reduced
glucuronidation capacity could play a role in the hepatic effects (e.g.,
cholestasis) seen in children on ECMO. Bilirubin is excreted as a
glucuronide conjugate. The DEHP metabolite, MEHP, also undergoes
glucuronidation and has been shown to interfere with bilirubin
conjugation (Sjoberg et al., 1991), perhaps as a competitive inhibitor
of glucuronidation.

DEHP is converted to the presumed toxic metabolite, MEHP, by lipase
enzymes in the gastrointestinal tract. Gastric lipase activity is high
in infants to aid in the digestion of fats in milk (Hamosh, 1996). Lee
et al. (1993) reported that gastric lipase activity peaks postnatally in
children at 28-33 weeks of age. Consequently, these children may be able
to convert DEHP to MEHP more efficiently than older children or adults
can.

Differences in intestinal permeability between children and adults may
also place children at greater risk, due to the greater potential for
children to absorb larger amounts of DEHP from the gastrointestinal
tract. Similarly, an increased permeability of the blood-testis barrier
in children as compared to adults could result in increased exposure of
the testes to DEHP or MEHP. The blood-testis barrier forms just before
puberty in humans (Furaya, 1978).

DEHP may exert toxic effects on the testes through depletion of zinc or
Vitamin E. It is important to note that both zinc and Vitamin E
deficiencies are not uncommon in preterm infants (Obladen et al., 1998;
Chan et al., 1999). Consequently, DEHP could exacerbate zinc and Vitamin
E deficiencies that occur in preterm infants from other causes.

Roth et al. (1988) have suggested that DEHP could contribute to the
development of hyaline membrane disease in children undergoing
mechanical ventilation. This disease results from insufficient
surfactant production in the lungs of newborn infants. Because of its
lipophilicity, Roth et al. (1998) speculated that DEHP could either
inhibit the formation or promote the degradation of surfactant. This
effect is less likely to be seen in the adult lungs because of the
increased ability of adults to produce surfactant. DEHP has also been
suggested as an etiologic agent for the development of necrotizing
enterocolitis in newborns. However, factors such as poor bowel perfusion
are more likely contributors to the pathogenesis of this disease than
exposure to DEHP.

In addition, children can receive a larger dose of DEHP than adults do
when dose is expressed on a mg/kg basis, for example, when the same
sized device can be used for both children and adults (e.g., an IV
administration set). Further, there are medical procedures that result
in DEHP exposure that are almost exclusively done on children, notable
among them are ECMO and exchange transfusion.

Since the Sjoberg et al. (1985a) and AdvaMed (2001) studies were
conducted using neonatal animals, it is not necessary to apply an
[additional]{.underline} UF to ensure that the TI is protective for
children. Nevertheless, it is prudent to consider the potentially
increased sensitivity of children to DEHP in selecting a value for UF1
for DEHP.

### 3.2.1.3 Critically ill or injured patients as a high risk subpopulation

Critically ill or injured patients may be at increased risk of
developing adverse health effects from DEHP, not only by virtue of
increased exposure, relative to the general population, but also because
of the physiological and pharmacodynamic changes that occur in these
patients, compared to healthy individuals. As mentioned above, factors
that increase the lipase-mediated bioactivation of DEHP or the
metabolism of MEHP via glucuronidation will increase the potential for
DEHP to induce adverse effects in exposed patients. Additional factors
that place patients at increased risk include: reduced renal elimination
capacity, uremia, protein malnutrition, reduced levels of antioxidants,
and impaired cardiovascular status. Two of these factors, protein
malnutrition and altered antioxidant status, are especially important
for DEHP-induced effects on the testes. Protein malnutrition may place
male patients at increased risk for adverse effects of DEHP on the
testes since a low protein diet has been shown to exacerbate the toxic
effects of DEHP on the testes in rats (Tandon et al., 1992). Unless
corrected by nutritional support, critically ill patients can enter a
state of protein malnutrition due to increased protein requirements.
Accelerated protein breakdown occurs in critically ill patients, such as
patients with acute renal failure or sepsis, and patients that have
undergone traumatic injuries and burns (Druml, 1998; Ishibashi et al.,
1998). Protein-energy malnutrition is a common complication of both
hemodialysis and peritoneal dialysis (Kopple, 1999). Patients undergoing
peritoneal dialysis experience protein loss through the dialysis
effluent (Brewer, 1999), a process that can lead to protein
malnutrition. Since a low protein diet can potentiate the testicular
toxicity of DEHP in rodents, the potential exists for patients with
protein malnutrition to be at increased risk for the development of
adverse reproductive effects relative to a healthy, well nourished
population.

Ishihara et al. (2000) recently reported that DEHP-induced testicular
atrophy can be prevented in rats by administration of ascorbic acid
(Vitamin C) and alpha-tocopherol (Vitamin E). If testicular atrophy can
be prevented by antioxidant administration, it is interesting to
speculate that testicular atrophy may be worsened in
antioxidant-deficient animals. This issue may be clinically important
since patients undergoing hemodialysis typically have low plasma levels
of ascorbate (e.g., Wang et al., 1999; Pereira et al., 2000; Metnitz et
al., 2000) and other antioxidants. In addition, patients with ARDS (and,
therefore, potentially may be treated with ECMO) have reduced levels of
ascorbate and alpha-tocopherol (Metnitz et al., 1999).

Reduction in prostatic and testicular zinc levels in rodents is a
hallmark of DEHP exposure and reduced zinc levels could play a role in
the etiology of DEHP-induced testicular toxicity, either through a
reduction of angiotensin-converting enzyme activity (Rahman et al.,
1999) or by failure to inhibit superoxide dismutase (SOD) activity which
could lead to increased superoxide anion production (Gavella et al.,
1999). As discussed above, a zinc-deficient diet has been shown to
produce a range of adverse testicular effects in rats and levels of zinc
in seminal fluid are lower in oligospermic men than in normospermic,
fertile men in some studies. Plasma zinc levels are reduced in patients
undergoing hemodialysis (Lee et al., 2000) and zinc deficiency is not
uncommon in preterm infants (Obladen et al., 1998). In addition,
chelating agents, such as disodium edetate (EDTA), that are found in
preparations of sedative agents, like propofol, can increase the urinary
excretion of zinc (Higgins et al., 2000). Since: 1) reduced testicular
zinc is seen in DEHP-exposed animals, 2) reduced zinc may play a role in
DEHP-mediated testicular damage and is associated with adverse effects
on the testis, and 3) low levels of zinc are seen in patients undergoing
hemodialysis and some newborns, the potential exists for the low zinc
levels seen in patients to exacerbate DEHP-mediated effects.

Altered health status may potentiate DEHP effects on organs other than
the testes. Rodents made hypovolemic by withdrawal of blood and held in
a hypovolemic state for a given period are more sensitive to the
pulmonary effects of DEHP than rodents that had blood withdrawn but
received an immediate replacement transfusion (Rubin and Chang, 1978).
Therefore, the injured lung may be more susceptible than a healthy lung
to adverse effects produced by intravenous administration of DEHP.

**3.2.1.4 Conclusions and their impact on the selection of values for
UF1**

-   Variability exists in the general population in the activity of
    lipase enzymes, which convert DEHP to MEHP, and
    glucuronosyltransferases, which are responsible for the metabolism
    and elimination of MEHP. Individuals with high lipase activity
    and/or low glucuronidation activity may be at increased risk of
    DEHP-induced effects, compared to the rest of the population.
    However, data are unavailable to quantitatively adjust the UF to
    account for this variability.

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-   Children are at increased risk following exposure to DEHP because
    they receive a greater dose of DEHP, relative to adults, and because
    of various pharmacokinetic differences between children and adults.
    However, the data used to derive the parenteral TI were obtained
    using neonatal animals (AdvaMed, 2001) and data from the Sjoberg et
    al. (1985b) study suggest that age-related differences in DEHP
    effects in rodents occur only after oral exposure. Nevertheless, it
    is prudent to consider this factor in deriving the UF1 for
    parenteral exposure, since the results of one study cannot be taken
    as conclusive evidence for a lack of age-related effects following
    parenteral exposure.

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-   Critically ill or injured patients can be at increased risk for
    DEHP-induced effects, relative to healthy individuals. However, data
    are unavailable to quantitatively adjust the UF to account for this
    increased sensitivity.

Collectively, these factors justify a value for UF1 of 10, since it
appears that some individuals in the general population may be more
sensitive to DEHP and since some critically ill patients almost
certainly are more sensitive to DEHP than healthy individuals.

# 

# 3.2.2 Interspecies extrapolation (UF2)

Use of the animal-to-human UF assumes that the effects seen in
experimental animals are relevant for humans. Selection of values \> 1
for this UF also assumes that humans are more sensitive than animals to
the compound on a mg/kg/day basis. Based on these assumptions, two
questions must be answered in the process of deriving an UF to account
for interspecies differences in response to a given dose of DEHP: 1) Are
the effects observed in DEHP-exposed experimental animals relevant for
humans? and 2) Are humans more sensitive to these effects than
experimental animals?

**3.2.2.1 Human relevance of effects seen in DEHP-exposed experimental
animals**

Although hepatic effects seen in rodents have been shown to occur via a
PPARα-dependent mechanism and are therefore assumed to be not relevant
for humans, Ward et al. (1998) demonstrated that DEHP exerts its effect
on the testes in mice via both PPARα-dependent and PPARα-independent
mechanisms. Following 8 weeks of exposure to DEHP in the diet, control
(+/+) mice developed moderate to severe focal tubular degenerative
lesions in the testes. In contrast, PPARα null (-/-) mice developed only
mild testicular changes.

Considerable attention has been paid to the potential for DEHP and other
phthalate esters to exert biological effects via an estrogenic
mechanism. However, it has recently been shown that DEHP (Gray et al.,
1999, 2000) and other phthalate esters (Mylchreest et al., 1998) exert
an anti-androgenic effect, most likely via reduction of testosterone
synthesis (Parks et al., 2000). There are no data to suggest that this
effect is limited to rodents. In addition, there are other mechanisms by
which DEHP and MEHP could exert adverse effects on the testes in
rodents, including inhibition of phospholipase A2, depletion of
testicular iron, alteration of antioxidant status, each of which are
presumed to be relevant for humans. As a result, there is no mechanistic
reason to assume that the adverse testicular effects seen in
DEHP-exposed rodents could not also occur in DEHP-exposed patients.

**3.2.2.2 Interspecies differences in sensitivity to DEHP**

Use of the default UF of 10 to account for interspecies differences in
potency is based on the default assumption that humans are more
sensitive to the toxic effects of chemical compounds than rodents are.
HIMA (1999), Koop (1999) and others have concluded that nonhuman
primates are less sensitive to the testicular effects of DEHP than
rodents are. If humans are similar to nonhuman primates in their
response to DEHP, then it could be argued that a value of 1 or even \< 1
would be appropriate for UF2, if the TI is based on the results of a
study conducted in rodents. Data on the comparative response of humans
and nonhuman primates to the effects of DEHP are unavailable to answer
this question directly, however, information on the similarity and
differences between spermatogenesis in humans and nonhuman primates and
on the similarity and differences in DEHP metabolism in humans and
nonhuman primates will be instructive in addressing this issue. It is
also important to examine whether nonhuman primates are less sensitive
than rodents to DEHP across all routes of exposure, or if this is a
route-specific effect.

***Interspecies differences in potency following oral exposure***

Data on the relative sensitivity of rodent and nonhuman primates to DEHP
have only been obtained following oral exposure to the compound. As
shown in Table 3-5, doses of DEHP that produce adverse effects in
rodents are without effect in nonhuman primates.

**Table 3-5. Comparison of the potency of DEHP in rats and nonhuman
primates following oral exposure (based on testicular effects)**

+----------+-------+-------+------+----------+-------+-------+------+
| **Oral   |       |       |      | ####     |       |       |      |
| Rat**    |       |       |      | ## Oral  |       |       |      |
|          |       |       |      | Nonhuman |       |       |      |
|          |       |       |      |  Primate |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+
| *        | **    | **NO  | *    | *        | **    | **NO  | *    |
| *Study** | Durat | AEL** | *LOA | *Study** | Durat | AEL** | *LOA |
|          | ion** |       | EL** |          | ion** |       | EL** |
+----------+-------+-------+------+----------+-------+-------+------+
|          |       |       |      |          |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+
| Rhodes   | 14    |       | 2000 | Rhodes   | 14    | 2000  |      |
| et al.   | days  |       |      | et al.   | days  |       |      |
| (1986)   |       |       |      | (1986)   |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+
| Agarwal  | 13    | 330   | 1000 | Pugh et  | 14    | 500   |      |
| et al.   | days  |       |      | al.      | days  |       |      |
| (1989)   |       |       |      |          |       |       |      |
|          |       |       |      | \(2000\) |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+
| Parmar   | 15    | 1000  | 2000 |          |       |       |      |
| et al.   | days  |       |      |          |       |       |      |
| (1986)   |       |       |      |          |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+
| Siddiqui | 15    | 500   | 1000 |          |       |       |      |
| and      | days  |       |      |          |       |       |      |
| Sr       |       |       |      |          |       |       |      |
| ivastava |       |       |      |          |       |       |      |
| (1992)   |       |       |      |          |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+
| Saxena   | 7     |       | 2000 |          |       |       |      |
| et al.   | days  |       |      |          |       |       |      |
| (1985)   |       |       |      |          |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+
| Oishi    | 14    |       | 2000 |          |       |       |      |
| (1985)   | days  |       |      |          |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+
| Gray and | 10    |       | 2800 |          |       |       |      |
| Gangolli | days  |       |      |          |       |       |      |
| (1986)   |       |       |      |          |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+
| Gray and | 10    | 2800  |      |          |       |       |      |
| Gangolli | days  |       |      |          |       |       |      |
| (1986)   |       |       |      |          |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+
|          |       |       |      |          |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+
| NTP      | 13    | 320   | 630  | Kurata   | 13    | 2800  |      |
| (1982)   | weeks |       |      | et al.   | weeks |       |      |
|          |       |       |      | (1998)   |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+
| Poon et  | 13    | 3.7   | 37.6 |          |       |       |      |
| al.      | weeks |       |      |          |       |       |      |
| (1997)   |       |       |      |          |       |       |      |
+----------+-------+-------+------+----------+-------+-------+------+

The data shown in Table 3-5 indicate that nonhuman primates are less
sensitive than rodents to DEHP following oral administration of the
compound.

Spermatogenesis in the marmoset is organizationally similar to the
process that occurs in humans, with regard to length of the
spermatogenic cycle, duration of spermatogenesis, and number of mitotic
divisions (Millar et al., 2000; Weinbauer et al., 2001). Consequently,
the marmoset has been described as an appropriate model for experimental
studies of human spermatogenesis. By analogy, it can be assumed that
DEHP-induced effects on this process seen in marmosets would be
applicable for humans. In addition, the pharmacokinetic behavior of DEHP
in nonhuman primates is more similar to that in humans than in rodents
(Albro et al., 1982); however, there are metabolic differences observed
among primate species. For example, intestinal cell preparations from
human mucosal cells may be more efficient in metabolizing a range of
phthalate diesters than similar preparations from baboon intestinal
cells (Lake et al., 1977), suggesting that humans can metabolize some
phthalate esters in the gut more efficiently than at least one species
of subhuman primate can. However, caution should be exercised in
comparing these data since the metabolic rate in rats and baboons is
expressed in units of μmole/hr/mg mucosal cell protein and metabolic
rate in human intestinal tissue is expressed in units of μmole/hr/mg
total protein. Nevertheless, if humans can metabolize an oral dose of
DEHP in the gut more effectively than marmosets can, then humans may be
more sensitive to the adverse effects of DEHP than subhuman primates
such as the marmoset are.

**Table 3-6. *In vitro* hydrolysis of phthalate diesters by intestinal
cell preparations (Lake et al., 1977)**

+----------------+-----------------+----------------+-----------------+
| **Phthalate    | **Rat**         | **Baboon**     | **Human**       |
| diester**      |                 |                |                 |
+----------------+-----------------+----------------+-----------------+
|                | Amount of       |                |                 |
|                | product formed  |                |                 |
+----------------+-----------------+----------------+-----------------+
|                | μmole/hr/mg     |                | μmole/hr/mg     |
|                | mucosal         |                | total protein   |
|                |                 |                |                 |
|                | cell protein    |                |                 |
+----------------+-----------------+----------------+-----------------+
| Dimethyl       | 1.14            | 6.67           | 197.5           |
+----------------+-----------------+----------------+-----------------+
| Diethyl        | 0.65            | 4.33           | 92.1            |
+----------------+-----------------+----------------+-----------------+
| Di-n-butyl     | 0.59            | 2.19           | 67.6            |
+----------------+-----------------+----------------+-----------------+
| Di-n-octyl     | 0.22            | 0.19           | 20.6            |
+----------------+-----------------+----------------+-----------------+
| DEHP           | 0.11            | 0.11           | 8.1             |
+----------------+-----------------+----------------+-----------------+

Since the results obtained with nonhuman primates are assumed to be
relevant for humans, 2) nonhuman primates appear to be less sensitive
than rodents to the effects of DEHP following oral administration, and
3) the TI is based on effects seen in rodents, then the value selected
for UF2 should reflect this difference in potency when deriving the oral
TI. However, it is possible for humans to metabolize DEHP more
effectively in the gut than some nonhuman primates can, thereby making
possibly making humans more sensitive than nonhuman primates to the
effects of DEHP. As a result, a value of 3 is selected for UF2 for use
in deriving the oral TI.

***Interspecies differences in potency following parenteral exposure***

If the differences in species sensitivity following oral exposure are
solely due to differences in pharmacokinetics, notably, the metabolic
conversion of DEHP in the gut and subsequent systemic absorption of
MEHP, then it can be assumed that rodents and nonhuman primates (and
humans) would be equally sensitive to the effects of DEHP following
parenteral exposure. Rhodes et al. (1986) reported that the marmoset
excreted only 2% of an orally administered dose of DEHP in the urine,
whereas the rat excretes about 50% of a similar dose of DEHP via the
urine. In addition, they estimated that the level of DEHP or its
metabolites in the tissues of the marmoset would be between one-fifth
and one-tenth the levels that would be present in rat tissues following
administration of the same dose of DEHP. Consequently, if the
pharmacodynamic sensitivity of the marmoset and rodent tissues were
similar, then similar effects should be seen in these species if the
orally administered dose was five- to ten-fold higher in the marmoset
than the rodent. The LOAEL for adverse testicular effects in rats
following long-term oral exposure is 37 mg/kg/day (Poon et al., 1997),
therefore, the comparable LOAEL expected for this effect in marmosets
should be on the order of 185 to 370 mg/kg/day, assuming pharmacodynamic
equivalence. However, the LOAEL for these effects in marmosets is much
higher, since long-term (13 week) administration of DEHP at doses up to
2500 mg/kg/day had no effect on the testes of exposed animals. These
findings suggest that other factors such as differences in the
pharmacodynamic sensitivity of the testes between these species could be
responsible for the refractoriness of the marmoset to the adverse
testicular effects of DEHP. In contrast to Rhodes et al. (1986), Astill
et al. (1986) found that a similar percentage of DEHP was excreted by
urinary and fecal routes in rats and cynomolgus monkeys following
administration of a relatively low gavage dose (100 mg/kg) of the
compound. Consequently, there may be little difference in the rate at
which DEHP is hydrolyzed and absorbed in rats and primates following
exposure to low doses of DEHP, a finding that further supports
pharmacodynamic differences as an underlying reason for species
differences in sensitivity to DEHP.

Pugh et al. (2000) reported elevated levels of DEHP and MEHP in the
liver of cynomolgus monkeys following oral administration of DEHP,
indicating that absorption and metabolism did take place; however, no
adverse testicular effects were seen in exposed animals. This finding
lends support to the hypothesis that nonhuman primates are less
sensitive than rodents to the effects of DEHP on the basis of
pharmacodynamic differences in sensitivity.

Data are unavailable on the relative sensitivity of the testes in
rodents and nonhuman primates to parenterally administered DEHP.
However, many studies indicate that the rat is especially sensitive to
the testicular effects of a number of reproductive toxicants, compared
to other species. Gray and Beamand (1984) demonstrated that *in vivo*
differences in sensitivity between rats and hamsters were in agreement
with the results produced *in vitro* on the detachment of germ cells in
testicular cell cultures in response to MEHP. Since the hamster and rat
cells were exposed to the same concentrations of MEHP, these results
suggest that pharmacodynamic differences in sensitivity are at least
partially responsible for the differences in response seen *in vivo*
between rats and hamsters with regard to testicular toxicity. Rats are
also more sensitive that other species to the adverse effects of other
testicular toxicants, including 2-methoxyethanol (Ku et al., 1994),
gallium arsenide (Omura et al., 1996), perfluoro-n-decanoic acid (Van
Rafelghem et al., 1987), carbendazim (Gray et al, 1990), ethane
dimethanesulfonate (Gray et al., 1995), 1,3-dinitrobenzene (Obasaju et
al., 1991), and 1,2-dibromo-3-chloropropane (Lag et al., 1989). Also, in
an *in vitro* assay designed to measure single-strand DNA breaks, Bjorge
et al. (1996) found that rat testicular cells were more sensitive to the
toxicant than humans cells for 6/15 compounds (either rat cells only
responded or rats cells responded at a lower concentration of the
toxicant) and equally sensitive for 8/15 (either no response in either
species for rats and humans cells responded at same concentration).
However, one of the compounds, acrylamide, produced a marginal response
in human cells, whereas none was seen in rats cells. Collectively, the
results of the studies described above suggest that testicular cells
from rats are more sensitive than those from humans or other species to
the adverse effects of reproductive toxicants. However, they cannot be
used with confidence to specifically state that rodent testicular cells
are more sensitive than human cells to the effects of phthalate esters,
since the compounds mentioned above may exert their effect on the testes
via a different mechanism of action than DEHP does.

The lack of testicular effects observed in nonhuman primates when the
dose is corrected for absorption and the weight-of-evidence suggesting
that rats are especially sensitive to a number of testicular toxicants,
compared to other species (including humans), raises the possibility
that pharmacodynamic as well as pharmacokinetic differences serve as the
basis for the differences in sensitivity between primates and rodents to
the effects of DEHP on the testes. These findings provide suggestive
(but not strong) evidence for a departure from the default value for UF2
used to derive a parenteral TI for DEHP. As a result, a value of 3 is
selected for this UF. It is important to note, however, that selection
of a value \> 1 for this parameter still implies that humans are more
sensitive than rodents to the testicular effects of DEHP, on a mg/kg/day
basis.

The definitive test of DEHP's ability to produce adverse effects in
humans is obviously to determine if such effects have been observed in
DEHP-exposed humans. HIMA (1999) noted, "Despite some testicular damage
to certain rodent species,^x^ no similar results have been observed in
studies relevant to human exposure to DEHP." Presumably, the phrase,
"studies relevant to human exposure to DEHP", refers to studies
conducted in nonhuman primates. To our knowledge, male reproductive
capacity has not been assessed in any study of humans following exposure
to DEHP, with the intent of determining whether DEHP was a causative
agent for reproductive problems. Although Ohlson and Hardell (2000)
reported a six-fold increase in the risk for seminoma in men
occupationally exposed to PVC, and suggested that the estrogenic effect
of DEHP could promote the growth of estrogen sensitive tumor cells in
exposed workers, the role of DEHP in producing this effect has not been
firmly established. Also, although a strikingly similar pattern of
hormonal and histological changes in the testis occurs in male patients
on hemodialysis and in experimental animals following exposure to DEHP,
it is not possible to determine from the existing data if DEHP plays a
role in the etiology of the effects seen in DEHP-exposed patients, since
uremia itself can produce these effects. Therefore, human data are
unavailable to answer the question of rodent vs. nonhuman primate vs.
human sensitivity to the testicular effects of DEHP.

**3.2.2.3 Conclusions and their impact on the selection of values for
UF2**

-   The adverse testicular effects seen in DEHP-exposed rodents could
    theoretically occur in DEHP-exposed humans, since there is no
    mechanistic reason to assume that the adverse testicular effects are
    species specific.

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-   Spermatogenesis in the marmoset is functionally similar to the
    process that occurs in humans. Therefore, nonhuman primates such as
    the marmoset are assumed to be appropriate models for humans with
    regard to the testicular effects of DEHP.

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-   Since nonhuman primates are less sensitive than rodents to DEHP
    following oral exposure, and since nonhuman primates serve as an
    appropriate model for human spermatogenesis, an UF of 1 is selected
    for UF2 used to derive the oral TI to DEHP. Some evidence suggests
    (but does not demonstrate) that factors other than species-specific
    differences in DEHP hydrolysis in the gut and absorption of MEHP may
    be responsible for the increased sensitivity of rats to the
    testicular effects of DEHP, compared to nonhuman primates and other
    species. Based on these factors, a value of 3 is selected for UF2
    used to derive the parenteral TI for DEHP. Although this value is a
    departure from the default for this UF, it is nevertheless
    consistent with the conservative assumption that humans are more
    sensitive to the testicular effects of DEHP than rodents are
    following IV exposure to DEHP.

**3.2.3 Data quality and relevance (UF3)**

Ideally, the conditions of a toxicity study used to derive the TI should
closely mimic exposure conditions in the clinical situation. If there
are differences that could result in a greater sensitivity in humans
compared to experimental animals, then an additional UF should be
applied to account for deficiencies in data quality.

The primary study upon which the parenteral TI is based (AdvaMed, 2001)
is indeed an excellent and relevant study. It employed a clinically
relevant route duration of exposure and the solubilization of DEHP in a
clinically relevant vehicle (Intralipid) minimizes concerns about the
influence of the vehicle on DEHP-induced effects. Further, the AdvaMed
(2001) study was conducted using a presumably relevant species at a
sensitive life-stage. However, there are some differences between the
conditions under which rodents were exposed to DEHP in the AdvaMed
(2001) study and the conditions under which patients are exposed in the
clinical setting (Table 3-6). For example, patients undergoing long-term
procedures such as hemodialysis can be exposed to DEHP for much longer
periods than were used in the AdvaMed (2001) study. In addition, humans
can be exposed to DEHP both prenatally and postnatally, whereas rodents
in the AdvaMed (2001) study received DEHP only in the postnatal period.
Also, unlike experimental animals in a controlled setting, patients can
be exposed to compounds that could potentiate the toxicity of DEHP.
Finally, animals in the AdvaMed (2001) study were healthy whereas
patients are often quite ill. The potentially increased sensitivity of
sick or injured patients to DEHP is taken into account in the value
selected for UF1; however, the other issues will be accounted for in
UF3. In addition, implications of the reversibility of the lesion in the
AdvaMed (2001) for TI derivation will be addressed in this section.
Also, modification of UF3 to account for the lack of a NOAEL value in
the Sjoberg et al. (1985a) study is explored below.

**Table 3-7. Comparison of experimental conditions used in AdvaMed
(2001) study and conditions in the clinical setting for neonates in a
NICU and adults undergoing hemodialysis.**

+--------------------------+---------------+------------+-------------+
| **Exposure Conditions**  | *             | ###        |             |
|                          | *Experimental | ### Clinic |             |
|                          | Animal        | al Setting |             |
|                          | Studies**     |            |             |
+--------------------------+---------------+------------+-------------+
|                          |               | **Neonate  | **Adult     |
|                          |               | in NICU**  | receiving   |
|                          |               |            | hem         |
|                          |               |            | odialysis** |
+--------------------------+---------------+------------+-------------+
|                          |               |            |             |
+--------------------------+---------------+------------+-------------+
| **IV route of exposure** | **Yes**       | **Yes**    | **Yes**     |
+--------------------------+---------------+------------+-------------+
| **Short-term duration of | **Yes**       | **Yes**    | **No**      |
| exposure**               |               |            |             |
+--------------------------+---------------+------------+-------------+
| **Similar life-stage of  | **Yes**       | **Yes**    | **No**      |
| exposure**               |               |            |             |
+--------------------------+---------------+------------+-------------+
| **Pre- and post-natal    | **No**        | **Yes**    | **NR**      |
| exposure**               |               |            |             |
+--------------------------+---------------+------------+-------------+
| **Coexposure to other    | **No**        | **Yes**    | **Yes**     |
| phthalates**             |               |            |             |
+--------------------------+---------------+------------+-------------+
| **Compromised health     | **No**        | **Yes**    | **Yes**     |
| status**                 |               |            |             |
+--------------------------+---------------+------------+-------------+

**3.2.3.1 Lack of data from a long-term study**

Ideally, a TI intended to be protective for long-term exposure to a
compound will be based on a NOAEL from a chronic toxicity study (one in
which dosing of the animal takes place over a significant proportion of
the animal's lifetime). However, studies of sufficient duration are
often not available when conducting a safety assessment. Such is the
case with the safety assessment of DEHP released from medical device
materials, since a valid, long-term toxicity study involving
administration of the compound via a parenteral route of exposure is not
available. Instead, data from the 12-day study conducted by Sjoberg et
al. (1985a), the 14- or 18-day studies conducted by Baxter (2000), and
the 21-day study conducted by AdvaMed (2001) will be used to assess the
potential for adverse effects to occur following exposure to DEHP in
medical procedures, such as hemodialysis, peritoneal dialysis and TPN
administration, which could take place repeatedly for extended periods.
When short-term data are used to derive a long-term TI, it is
commonplace to employ an UF to account for the assumed greater potency
of the compound following long-term as compared to short-term exposure.
However, it is likely that the LOAEL following long-term parenteral
exposure of rodents to DEHP would not be lower than the LOAEL reported
in the relatively short-term studies of Sjoberg et al. (1985a) and
AdvaMed (2001), since exposure in the short-term studies took place in
what is assumed to be a critical and sensitive period for testicular
effects and because DEHP has a relatively short half-life and is not
expected to accumulate in the body. This conclusion is supported
empirically by the similarity in the NOAEL values from the subchronic
Poon et al. (1997) study (3.7 mg/kg/day) and the chronic David et al.
(2000) study (5.8 mg/kg/day). Therefore, although the parenteral TI is
derived using short-term data, it is assumed to be health-protective
even for long-term exposure to DEHP, since it is based on the most
sensitive endpoint (testicular effects) observed following long- or
short-term exposure to DEHP and is also based on data obtained following
exposure of what is assumed to be the most sensitive animal species
exposed during a sensitive period of development. Therefore, an
additional UF to account for the lack of a long-term study will not be
applied to the NOAEL and LOAEL from the short-term studies of Sjoberg et
al. (1985a), Baxter (2000), and AdvaMed (2001) studies to derive a
long-term parenteral TI.

**3.2.3.2 Lack of data from a study involving pre- and postnatal
exposure**

The results of the study conducted by Arcadi et al. (1998) were not used
to derive an oral TI for DEHP, because of uncertainty about the dose of
the compound that was actually received by maternal animals and their
pups; however, this study did illustrate that exposure to DEHP during
gestation, followed by postnatal exposure, resulted in the development
of adverse testicular effects in the offspring at doses approximately an
order of magnitude lower than those that produced adverse effects in
rodents exposed only in the postnatal period (based on LOAELs from the
Poon et al., 1997 and David et al., 2000 studies). Similarly, the
results of the studies by Moore et al. (2001) and Wine et al. (1997)
point out that male rats are more sensitive to the adverse testicular
effects of phthalate esters following continuous multigenerational
exposure (including *in utero* and lactational exposure) to DEHP and
DBP, respectively, than if the animals were only exposed during the
postnatal period. However, animals in the studies upon which the
parenteral TI is based were exposed to phthalate esters only during the
postnatal period. Based on the results of the Arcadi et al. (1998),
Moore et al. (2001), and Wine et al (1997) studies, it is possible that
the LOAELs in the Sjoberg et al. (1985a) and AdvaMed (2001) studies
would have been lower if exposure had taken place both prenatally and
postnatally. Exposure during the pre- and postnatal periods more
accurately reflect the clinical situation, since neonates exposed to
DEHP and MEHP from PVC devices could also have been exposed to phthalate
esters *in utero*. In contrast, maternal rats in the laboratory
environment are exposed to essentially no phthalate esters during the
gestational period (Kessler et al., 2001). Since: 1) prenatal exposure
followed by postnatal exposure can increase the sensitivity of rodents
to the testicular effects of DEHP, as compared to postnatal exposure
only, 2) humans can be exposed to DEHP and other phthalate esters both
prenatally and postnatally, and 3) rodents in the studies used to derive
the TI were only exposed postnatally, then it is prudent to take this
factor into account when deriving a TI for DEHP when dosing occurs
during the entire perinatal period.

The potential for adverse effects to occur in humans (or rodents)
exposed both pre- and postnatally to DEHP is obviously related to the
dose of DEHP received. Adverse testicular effects were seen in rat pups
in the Arcadi et al. (1998) study following maternal exposure to DEHP at
a dose of about 3 mg/kg/day and the lowest dose in the Moore et al.
(2001) study, 375 mg/kg/day, produced these effects (however, no NOAEL
was identified in the Moore et al., 2001 study). In contrast, Kohn et
al. (2000) estimated the maximum dose of DEHP received by women aged
20-40 years to be 10 μg/kg/day, based on the data reported by Blount et
al. (2000) on urinary excretion of phthalates. However, total maximum
exposure of women of reproductive age to all phthalate esters is on the
order 0.3 mg/kg/day, based on the estimates derived by Kohn et al.
(2000). In addition, pregnant women can be exposed to DEHP from medical
procedures. For example, women who experience hyperemesis gravidarum are
typically rehydrated with IV fluids (Power et al., 2001); however,
further nutritional support can be provided either with TPN (Folk and
Leslie, 2001; Subramaniam et al., 1998) or enteral feeding (Hsu et al.,
1996). As shown previously in Table 2-24, patients receiving nutritional
support with TPN or enteral feeding can receive a daily DEHP dose of
about 0.14 mg/kg/day. Higher *in utero* exposures could be expected if
the mother was exposed to DEHP from hemodialysis, however, female
patients with chronic renal failure on hemodialysis experience a much
greater incidence of infertility than their counterparts without renal
disease. Only about 1-2% of women on hemodialysis become pregnant, and
only about 40-50% of those women give birth to live infants (Bagon et
al., 1998; Okundaye et al., 1998; Toma et al. 1999). Consequently, the
number of infants that experience both high dose prenatal exposure to
DEHP (assuming maternal exposure to DEHP from hemodialysis) and high
dose postnatal exposure via procedures such as ECMO is likely to be very
small.

The results of the above studies suggest that neonates can be prenatally
exposed to phthalates from maternal exposure to phthalates in the
environment (e.g., use of personal care products) and a certain number
of newborns will also receive prenatal exposure to DEHP following
maternal exposure to the compound during medical procedures such as
enteral or parenteral feeding. The dose of DEHP received by the mother
undergoing these procedures may be only about an order of magnitude less
than the dose that caused adverse testicular effects in the offspring of
rodents treated orally with DEHP. Consequently, a TI should be derived
that is sufficiently protective for pre- and post-natal exposure to
DEHP.

**3.2.3.3 Lack of data from a study involving coexposure to multiple
phthalate esters**

The implications of coexposure of patients to MEHP and DEHP have been
addressed elsewhere (Annex C); however patients are exposed to phthalate
esters other than DEHP and MEHP in the hospital environment. Although
DEHP is by far the most commonly used plasticizer PVC, dibutyl phthalate
(DBP), diethyl phthalate (DEP), dimethyl phthalate (DMP), diisobutyl
phthalate (DIP), and butyl 2-ethylhexyl phthalate (BEP) have also been
identified in extracts from PVC medical devices. For example, Khaliq et
al. (1992) quantified levels of DEHP, DBP and DMP released from PVC
nasogastric tubing. DBP and DEP have been identified as components of
PVC used for devices such as microfilters, butterfly catheters, infusion
tubing, infusion bags, and intestinal tubing at levels ranging from ≥ 1%
to \< 20% of the total volatiles extracted from the device (Wahl et al.,
1999). DBP has also been shown to leach from denture base material
(Lygre et al., 1995). Patients undergoing peritoneal dialysis are
exposed to both DEHP and DBP from the dialysate (Sugimura et al., 2001)
and multiple phthalates have been identified in food served to hospital
patients (Tsumura et al., 2001). Patient exposure to multiple phthalates
is also evidenced by data reported by Ching et al. (1981). It is
interesting to note in the Ching et al. (1981) study that levels of DBP
in the serum of surgical patients exceeded that of DEHP in many cases.

In contrast to the clinical situation, rats in the Sjoberg et al.
(1985a), Baxter (2000), and AdvaMed (2001) studies were exposed only to
DEHP and there is very little background exposure to other phthalate
esters (Kessler et al., 2001). Since the two phthalate esters with the
highest exposures (DEHP and DBP) have similar effects on the testes and
are thought to exert these effects via an antiandrogenic mechanism, the
potential exists for the LOAEL in the Sjoberg et al. (1985a) and AdvaMed
(2001) studies to have been lower if the rats had been coexposed to
multiple phthalate esters, as occurs in the clinical situation.

# 3.2.3.4 Lack of a NOAEL value

In cases where a NOAEL is not identified in a study, it is customary to
apply an UF of 3 to 10 to the LOAEL to estimate the NOAEL. Although the
parenteral TI is derived from the NOAEL in the AdvaMed (2001) study, the
TI could also be derived from the LOAEL in the Sjoberg et al. (1985a)
study. Since the effects seen at the LOAEL dose in the Sjoberg et al.
(1985a) study are fairly subtle, an UF of 3 will be applied to the LOAEL
to estimate the NOAEL.

**3.2.3.5 Reversibility of DEHP- or MEHP-induced testicular lesions**

It has been argued that a smaller UF can be applied when deriving a TI
if the effects seen at the LOAEL are reversible (e.g., Gaylor et al.,
1999). Recovery of at least some male reproductive capacity (sperm
count, sperm motility and sperm morphology) occurred in DEHP-exposed
rats at the end of the recovery period in the AdvaMed (2001) study.
Although these results are encouraging for neonates exposed to DEHP and
MEHP, the following factors should be considered:

-   Although recovery was seen in functional parameters, testicular
    atrophy persisted at the end of the recovery period in rats exposed
    to DEHP either orally or by IV injection. Consequently, the adverse
    testicular effects of DEHP were not completely reversible. These
    findings are consistent with those reported by Oishi (1985), who
    found that testicular weight did not return to normal in
    DEHP-treated rats and spermatogenesis continued to be impaired 45
    days after cessation of exposure to DEHP. Agarwal et al. (1986) also
    noted only partial recovery from the testicular effects in rats
    following cessation of exposure to DEHP.

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-   Although some functional indices of male reproductive capacity
    recovered in DEHP-exposed rodents, fertility was not assessed by
    mating the animals. Therefore, it cannot be said with certainty that
    functional impairment of reproductive capacity did not occur.

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-   As discussed above, vitamin deficiency potentiates DEHP-induced
    aspermatogenesis (Ishihara et al., 2000). Since animals in the
    AdvaMed (2001) study were presumably not vitamin deficient, it is
    possible that functional indices of male reproductive capacity would
    not have returned to normal in vitamin-deficient animals.

Based on these considerations, it is not appropriate to reduce the value
for UF3 (and consequently, the value of the TI) to account for the
reversibility of the functional deficits following a recovery period;
however, the recovery of these indices of male reproductive capacity in
the AdvaMed (2001) study is nevertheless encouraging.

**3.2.3.6 Conclusions and their impact on the selection of values for
UF3**

-   An additional UF to account for the lack of a long-term study will
    not be applied to the NOAEL and LOAEL from the short-term studies of
    Sjoberg et al. (1985a), Baxter (2000), and AdvaMed (2001) to derive
    a long-term parenteral TI.

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-   The following factors will be taken into account when selecting a
    value for UF3: increased sensitivity to DEHP-induced testicular
    effects during pre- and postnatal exposure and the possibility that
    humans can be exposed to phthalates other than DEHP and MEHP that
    exert their effect via a similar mechanism of action.

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-   The potentially increased sensitivity of sick or injured patients to
    DEHP was taken into account in the selection of a value for UF1.

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-   Where a LOAEL is used to derive the TI, an UF of 3 is justified,
    based on the severity of effects seen at the LOAEL and the
    relationship of LOAEL to NOAEL values in other studies.

-   Some but not all of the adverse testicular effects seen in
    DEHP-exposed rodents in the AdvaMed (2001) study were reversible
    following a recovery period. Therefore, the UF will not be adjusted
    to account for reversibility.

Collectively, these factors justify a value for UF3 of 3 when a NOAEL is
used to derive the TI and 10 (approximately 3 x 3) when a LOAEL is used
to derive the TI.

# 

# 3.3 Application of Modifying Factors to Derive Parenteral and Oral TI Values (Step 3)

Based on the considerations discussed above, the following MFs will be
used to derive the TI values for DEHP via oral and parenteral routes
(Table 3-8).

**Table 3-8 Modifying Factors for Derivation of TI Values for DEHP**

+--------+---------------------------+----+----+----+----------------+
| **R    | **Endpoint**              | ## | *  | *  | **Modifying    |
| oute** |                           | ## | *U | *U | Factor**       |
|        |                           | ## | F2 | F3 |                |
|        |                           |  U | ** | ** |                |
|        |                           | F1 |    |    |                |
+--------+---------------------------+----+----+----+----------------+
|        |                           |    |    |    |                |
+--------+---------------------------+----+----+----+----------------+
| Pare   | NOAEL from Baxter (2000,  | 10 | 3  | 3  | 100            |
| nteral | 2001)                     |    |    |    |                |
+--------+---------------------------+----+----+----+----------------+
|        | LOAEL from Sjoberg et al. | 10 | 3  | 10 | 300            |
|        | (1985a)                   |    |    |    |                |
+--------+---------------------------+----+----+----+----------------+
| Oral   | NOAEL from Poon et al.    | 10 | 3  | 3  | 100            |
|        | (1997)                    |    |    |    |                |
+--------+---------------------------+----+----+----+----------------+

Application of these modifying factors to the NOAEL value reported by
Baxter (2000, 2001) following parenteral exposure, the LOAEL values
reported by Sjoberg et al. (1985a) following IV exposure and the NOAEL
reported by Poon et al. (1997) following oral exposure yields the
following TI values (Table 3-9).

**Table 3-9 TI Values for DEHP**

+--------+----------------------+------------+----------+------------+
| **R    | **Endpoint**         | **NOAEL or | **M      | **TI**     |
| oute** |                      | LOAEL      | odifying |            |
|        |                      | value      | Factor** | **(mg      |
|        |                      | (mg        |          | /kg/day)** |
|        |                      | /kg/day)** |          |            |
+--------+----------------------+------------+----------+------------+
| Pare   | NOAEL from Baxter    | 60         | 100      | 0.60       |
| nteral |                      |            |          |            |
|        | (2000, 2001)         |            |          |            |
+--------+----------------------+------------+----------+------------+
|        | LOAEL from Sjoberg   | 250        | 300      | 0.80       |
|        | et al. (1985a)       |            |          |            |
+--------+----------------------+------------+----------+------------+
| Oral   | NOAEL from Poon et   | 3.7        | 100      | 0.04       |
|        | al. (1997)           |            |          |            |
+--------+----------------------+------------+----------+------------+

No parenteral health-based exposure limits have been derived previously
for DEHP, however, the TI value derived for parenteral exposure is
equivalent to the dose of DEHP received following exposure to this
compound at the OSHA 8-hour PEL (OSHA, 1988), assuming 100% absorption
(5 mg/m^3^ x 10m^3^/day x 1/70 kg = 0.7 mg/kg/day).

Existing health-based exposure limits based on noncancer effects seen
after oral exposure have been derived by other regulatory agencies and
advisory groups (Table 3-10). Comparison of these values to the TI value
derived by CDRH for DEHP reveals that the CDRH-derived value is
consistent with the health-based exposure limits derived for DEHP by the
Health Canada, the OECD, U.S. EPA, and the EU Scientific Committee on
Toxicity, Ecotoxicity and the Environment (CSTEE).

**Table 3-10 Existing health-based exposure limits for DEHP based on
noncancer effects (oral exposure)**

+---------------+---+-----------+-----------+-------------+--------------+
| ######        | # |           |           |             |              |
|               | # |           |           |             |              |
|               | # |           |           |             |              |
|               | # |           |           |             |              |
|               | # |           |           |             |              |
|               | # |           |           |             |              |
|               |   |           |           |             |              |
|               | A |           |           |             |              |
|               | g |           |           |             |              |
|               | e |           |           |             |              |
|               | n |           |           |             |              |
|               | c |           |           |             |              |
|               | y |           |           |             |              |
+---------------+---+-----------+-----------+-------------+--------------+
|               |   | **EU**    | **Health  | **OECD**    | **U.S. EPA** |
|               |   |           | Canada**  |             |              |
|               |   | **CSTEE** |           |             |              |
+---------------+---+-----------+-----------+-------------+--------------+
|               |   |           |           |             |              |
+---------------+---+-----------+-----------+-------------+--------------+
| Type of Value |   | Guidance  | Tolerable | Tolerable   | Reference    |
|               |   | value for | Daily     | Daily       | Dose (RfD)   |
|               |   | ex        | Intake    | Intake      |              |
|               |   | tractable | (TDI)     | (TDI)       |              |
|               |   | amount    |           |             |              |
+---------------+---+-----------+-----------+-------------+--------------+
| Risk Value    |   | 0.05      | 0.044^1^  | 0.04        | 0.022        |
|               |   |           |           |             |              |
| (mg/kg/day)   |   |           |           |             |              |
+---------------+---+-----------+-----------+-------------+--------------+
| Basis         |   | NOAEL     | NOAEL     | NOAEL       | LOAEL        |
|               |   |           |           |             |              |
|               |   | 5         | 44        | 37.5        | 19 mg/kg/day |
|               |   | mg/kg/day | mg/kg/day | mg/kg/day   |              |
+---------------+---+-----------+-----------+-------------+--------------+
| Uncertainty   |   | 100       | 1000      | 1000        | 1000         |
| Factor        |   |           |           |             |              |
+---------------+---+-----------+-----------+-------------+--------------+
| Critical      |   | Hepatic   | Maternal  | Ter         | Liver        |
| Organ or      |   | P         | and Fetal | atogenicity |              |
| Effect        |   | eroxisome |           |             |              |
|               |   | Prol      |           |             |              |
|               |   | iferation |           |             |              |
+---------------+---+-----------+-----------+-------------+--------------+
| Species       |   | Rat       | Mouse     | Mouse       | Guinea pig   |
+---------------+---+-----------+-----------+-------------+--------------+
| Study         |   | RIVM      | Wolk      | Tyl et al.  | Carpenter et |
|               |   | (1992)    | owski-Tyl | (1988)      | al. (1953)   |
|               |   |           | et al.    |             |              |
|               |   |           | (1984)    |             |              |
+---------------+---+-----------+-----------+-------------+--------------+

^1^Currently undergoing review

4.  Risk Characterization

In the risk characterization step of the safety assessment, exposure
information presented in Section 2.0 is compared to the TI values
derived in Section 3.0 to assess the likelihood that exposure to DEHP
could cause adverse effects in exposed patients.

In Table 4-1, TI values for DEHP are compared to doses of DEHP received
by patients undergoing various medical procedures. When assessing the
significance of the TI/Dose ratios shown in Table 4-1, it is important
to keep in mind that this comparison should not be viewed as a
bright-line value, but rather as a general index of the safety. In other
words, an TI/Dose ratio \> 1 does not necessarily mean that a compound
is "safe", nor does a TI/Dose \< 1 indicate that adverse effects are
likely in humans. Rather, these values should be used in a relative
sense to assess the likelihood that exposure to a compound will cause
adverse effects in humans. Two other factors should be kept in mind as
well when interpreting the significance of these values: 1) the TI is a
value with uncertainty that spans perhaps an order of magnitude (Dourson
et al., 1996), and 2) TI/Dose ratios based on a comparison between
short-term or one-time exposures (e.g., acute transfusion) and a TI
based on a repeat-dose toxicity study are likely to be conservative.

This information is being provided to risk managers to assist with
regulatory decision-making regarding the safety of PVC medical devices.
Factors such as the relevance of the data for humans, uncertainties
associated with the toxicity and exposure data, and any benefits
conferred by the use of DEHP as a plasticizer for PVC used in medical
devices will be considered along with the TI/Dose ratios values in
making any regulatory decisions.

The TI/Dose ratios listed in Table 4-1 will allow CDRH to draw
conclusions about the risk posed by patient exposure to DEHP in various
clinical scenarios. These conclusions are as follows.

## **4.1 Conclusions Based on TI/Dose Ratios**

######### IV infusion of crystalloid fluids and drugs

Based on the results of the safety assessment, CDRH concludes that there
is little to no risk posed by patient exposure to the amount of DEHP
released from PVC IV bags following infusion of crystalloid fluids
(e.g., normal saline, D5W, Ringers Lactate). Further, there is little
risk posed by exposure to the amount of DEHP released from PVC bags used
to store and administer drugs that require a pharmaceutical vehicle for
solubilization, when label instructions are followed. Administration of
propofol for conscious sedation of infants has the potential to result
in the administration of large doses of DEHP; however, propofol is not
approved for this indication in the US.

***Total Parenteral Nutrition (TPN)***

The dose of DEHP received by adult patients receiving TPN admixtures is
estimated to be less than the TI, suggesting that there is little
concern for DEHP-mediated effects in these patients. In addition,
non-PVC bags and tubing are typically used to administer TPN, further
lessening the concern about DEHP-mediated effects. Although the TI/dose
ratio suggests little concern in adult patients receiving TPN,
consideration should be given to the use of non-PVC bags and tubing when
administering TPN to pregnant women who require nutritional support for
the treatment of hyperemesis gravidarum.

The dose of DEHP received by neonates undergoing TPN supplementation is
uncertain. The results of one study suggest that neonates can receive a
very high dose of DEHP, whereas another suggests that neonates receive
doses of DEHP from TPN that are equivalent to the TI. Therefore,
depending on the data used to derive the TI/dose ratio, neonates
receiving TPN admixtures with lipid may be at increased risk of
DEHP-mediated adverse effects.

##### *Blood transfusion*

Relatively high doses of DEHP can be received by patients who are
transfused with large volumes of blood and blood products over a short
period (e.g., trauma or surgical patients receiving massive
transfusions). However, the TI/dose ratio for this procedure is likely
to overestimate the actual risk to these patients, since it is intended
to be protective of long-term exposure, compared to relatively
short-term exposure in acute transfusions. In contrast, a patient
undergoing a routine, elective surgical procedure typically receives
about two units of packed red blood cells. Transfusion of this volume of
blood will result in a DEHP dose equivalent to the TI value,
approximately 0.5 mg/kg/day. Long-term transfusion of blood to patients
with anemia results in a DEHP dose about an order of magnitude lower.
Similarly, infants who receive replacement transfusions in the NICU
receive relatively small DEHP doses from the transfusions. Apheresis
donors are exposed to relatively little DEHP when the dose is
time-averaged over an extended period. Consequently, there is little
concern about DEHP-associated adverse effects developing in persons
donating platelets or plasma.

Two subpopulations of patients that may be at increased risk from
exposure to DEHP following transfusions are infants undergoing exchange
transfusion and adults receiving ECMO. However, neither of these
procedures is done very often, so the patient population exposed to
relatively large doses of DEHP via exchange transfusion or replacement
transfusion of adults on ECMO is expected to be small.

##### *Cardiopulmonary bypass and ECMO*

The aggregate dose of DEHP received by adults undergoing cardiopulmonary
bypass procedures may equal of exceed the TI in some patients. However,
heparin-coated tubing is used in about half of "special" or high risk
cases and about 17% of "routine" cases (Mejak et al., 2000). Since
little DEHP is released from heparin-coated tubing (Karle et al., 1997),
the dose of DEHP received by many patients undergoing cardiopulmonary
bypass will be less than those undergoing the procedure where uncoated
PVC tubing is used.

The dose of DEHP received by neonates undergoing ECMO may exceed the
parenteral TI by more than 20-fold, based on the exposure estimate from
one study. However, a TI/dose close to 1 for this procedure can be
derived using dose information from another study. Therefore, the risk
posed by patient exposure to the amount of DEHP released during ECMO is
uncertain. It is important to point out that no acute effects were seen
in neonates undergoing this procedure in the recent study by Karle et
al. (1997); however, it is equally important to point out that
testicular toxicity (the assumed most sensitive effect in humans and
other species) was not assessed in this study.

##### *Hemodialysis and peritoneal dialysis*

Based on recent data on the amount of DEHP retained by patients on
hemodialysis, there is little concern regarding exposure to DEHP in
patients undergoing this procedure. However, these patients may
represent a sensitive subpopulation to the effects of DEHP because of
reduced elimination capacity and the potential for uremia and coexposure
to other compounds to potentiate the effects of DEHP.

Since very little DEHP is released into peritoneal dialysis fluid, the
corresponding risk of systemic effects developing following exposure to
this low dose of DEHP is also low.

##### *Enteral nutrition and breastfeeding*

Lipid in enteral nutrition solutions can leach out considerable doses of
DEHP from PVC bags and tubing. As a result, these patients may be at
increased risk of developing DEHP-mediated effects if PVC bags and
tubing are used to deliver the enteral nutrition solutions.

Based on theoretical estimates, it is possible for nursing infants of
mothers on hemodialysis to receive very high doses of DEHP; however the
exact dose received by these babies is highly uncertain. Because of the
level of uncertainty in this estimate, a TI/Dose ratio was not derived
for this means of exposure to DEHP. Also, because women on hemodialysis
are typically infertile, the population of infants exposed in this
manner is thought to be very small.

Bags used to store breast milk following the use of a breast pump are
typically made from polyethylene or nylon coated with polyethylene.
Consequently, it is not expected that infants will be exposed to any
DEHP released from a breast pump or milk storage bags.

***Aggregate exposure to DEHP from multiple medical devices***

DEHP dose estimates typically do not take into account exposure of
patients to multiple PVC devices. Consequently, it is important to
assess the potential risk of patients in various clinical scenarios by
taking into account aggregate exposure to DEHP from multiple devices.
For example, neonates in the NICU environment are exposed to DEHP from
multiple devices. Based on the dose of DEHP received in such procedures
as intravenous administration of sedatives, administration of TPN and
replacement transfusion, all common procedures in the NICU, it is
possible to estimate that a 4 kg infant could receive a DEHP dose on the
order of 3 mg/kg/day for a periods of weeks or months. The resulting
TI/dose ratio in this setting is 0.2. In other words, the dose of DEHP
received by some infants from device-related sources could be 5-fold
greater than the TI. If the neonate is also undergoing ECMO treatment,
the TI/dose ratio drops to around 0.05, indicating that the dose of DEHP
received by some infants from device-related sources could be 20-fold
greater than the dose of DEHP that is not expected to result in adverse
effects following intravenous exposure.

**Table 4-1. Comparison of Tolerable Intake (TI) Values for DEHP to the
dose of DEHP received by adult and neonatal patients undergoing various
medical procedures.**

+------------------------+----------+----------+----------+----------+
|                        | **Ad     |          | **Neon   |          |
|                        | ult^1^** |          | ate^2^** |          |
+------------------------+----------+----------+----------+----------+
|                        | **DEHP   | *        | **DEHP   | *        |
|                        | dose**   | *TI/dose | dose**   | *TI/dose |
|                        |          | ra       |          | ra       |
|                        | **(mg/k  | tio^3^** | **(mg/k  | tio^3^** |
|                        | g/day)** |          | g/day)** |          |
+------------------------+----------+----------+----------+----------+
| **Infusion of          | 0.005    | 120      | 0.03     | 20       |
| crystalloid IV         |          |          |          |          |
| solutions**            |          |          |          |          |
+------------------------+----------+----------+----------+----------+
|                        |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| **IV infusion of drugs | 0.15     | 4        | 0.03     | 20       |
| requiring              |          |          |          |          |
| pharmaceutical         |          |          |          |          |
| vehicles for           |          |          |          |          |
| solubilization**       |          |          |          |          |
+------------------------+----------+----------+----------+----------+
|                        |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| #####                  |          |          |          |          |
| ### TPN administration |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| Without added lipid    | 0.03     | 20       | 0.03     | 20       |
+------------------------+----------+----------+----------+----------+
| With added lipid       | 0.13     | 5        | 2.5      | **0.2**  |
+------------------------+----------+----------+----------+----------+
| EVA bag with PVC       | 0.06     | 10       |          |          |
| tubing                 |          |          |          |          |
+------------------------+----------+----------+----------+----------+
|                        |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| ####                   |          |          |          |          |
| #### Blood transfusion |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| Trauma patient         | 8.5      | **0.1**  |          |          |
+------------------------+----------+----------+----------+----------+
| Transfusion/ECMO pts.  | 3.0      | **0.2**  |          |          |
+------------------------+----------+----------+----------+----------+
| Exchange transfusion   |          |          | 22.6     | **0.02** |
+------------------------+----------+----------+----------+----------+
| Replacement            |          |          | 0.3      | 2        |
| transfusion            |          |          |          |          |
|                        |          |          |          |          |
| Neonate in NICU        |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| Replacement            | 0.09     | 7        |          |          |
| transfusion            |          |          |          |          |
|                        |          |          |          |          |
| Correction of anemia   |          |          |          |          |
| in                     |          |          |          |          |
|                        |          |          |          |          |
| Patients receiving     |          |          |          |          |
|                        |          |          |          |          |
| Chemotherapy and       |          |          |          |          |
| patients               |          |          |          |          |
|                        |          |          |          |          |
| with sickle cell       |          |          |          |          |
| disease                |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| Replacement            | 0.28     | 2        |          |          |
| transfusion            |          |          |          |          |
|                        |          |          |          |          |
| surgical patient       |          |          |          |          |
| undergoing             |          |          |          |          |
|                        |          |          |          |          |
| CABG                   |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| Treatment of clotting  | 0.03     | 20       |          |          |
|                        |          |          |          |          |
| Disorders with         |          |          |          |          |
|                        |          |          |          |          |
| Cryoprecipitate        |          |          |          |          |
+------------------------+----------+----------+----------+----------+
|                        |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| ########               |          |          |          |          |
| Cardiopulmonary bypass |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| CABG                   | 1        | **0.6**  |          |          |
+------------------------+----------+----------+----------+----------+
| Orthotopic heart       | 0.3      | 2        |          |          |
| transplant             |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| Artificial heart       | 2.4      | **0.3**  |          |          |
| transplant             |          |          |          |          |
+------------------------+----------+----------+----------+----------+
|                        |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| ######## ECMO          |          |          | 14       | **0.04** |
+------------------------+----------+----------+----------+----------+
|                        |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| ######## Apheresis     | 0.03     | 20       |          |          |
+------------------------+----------+----------+----------+----------+
|                        |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| **Hemodialysis**       | 0.36     | 2        |          |          |
+------------------------+----------+----------+----------+----------+
|                        |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| **Peritoneal           | \< 0.01  | \> 60    |          |          |
| dialysis**             |          |          |          |          |
+------------------------+----------+----------+----------+----------+
|                        |          |          |          |          |
+------------------------+----------+----------+----------+----------+
| **Enteral nutrition**  | 0.14     | **0.3**  | 0.14     | **0.3**  |
+------------------------+----------+----------+----------+----------+

^1^ 70 kg body weight

^2^ 4 kg body weight

^3^ Based on TI of 0.6 mg/kg/day for parenteral exposures and 0.04
mg/kg/day for enteral nutrition

2.  **Aggregate Exposure to DEHP and MEHP**

In addition to DEHP, patients can be exposed to the DEHP metabolite,
MEHP. This compound is formed exogenously by lipases in stored plasma or
blood or by hydrolysis in stored and heated IV fluid. As a result, some
of the DEHP that is released into stored blood, plasma, or IV fluids
will be converted to MEHP before reaching the patient. Exposure to MEHP
is important since this compound is thought to be the toxic metabolite
of DEHP and because it is more potent than DEHP in producing adverse
effects. A method was developed to estimate the aggregate dose of DEHP
and MEHP and to express this dose on the basis of DEHP-equivalents
(Annex C). However, because of uncertainties associated with the
relative potency of DEHP:MEHP and resulting estimates of DEHP equivalent
dose, the TI/Dose ratios based on the dose of DEHP-equivalents received
by patients will not be used to support regulatory decision making.

3.  **Conclusions Based on Nonsystemic Effects**

The conclusions reached in the safety assessment are based solely on the
potential for DEHP to cause in adverse systemic effects in exposed
patients, based on TI values derived from animal studies. However, the
clinical significance of various nonsystemic effects produced by DEHP is
explored in Annex D. The ability of DEHP to alter the hemocompatibility
of PVC tubing or result in adsorption of drugs to PVC tubing may be the
most clinically important endpoints to consider in the risk management
phase of the assessment, depending on the device.

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**Annex A. Exposure Assessment**

Section 2.0 of the main document provides an overview of the doses of
DEHP received by patients undergoing various medical procedures. This
annex provides more information on how these dose estimates were
derived.

DEHP is released from a wide variety of PVC medical devices. A partial
list of these devices is provided in Table A-1.

Table A-1. PVC medical devices known to release DEHP

  ----------------------------------- -----------------------------------
  IV storage bags                     Ventilator tubing

  IV infusion sets                    Endotracheal tubes

  IV infusion catheters               Nasogastric tubes

  Blood storage bags                  Enteral and parenteral nutrition
                                      storage bags

  Blood administration sets           Urinary catheters

  PVC exam gloves                     Suction catheters

  Chest tubes                         Nasal cannula tubing

  Hemodialysis tubing                 Syringes

  Extracorporeal membrane oxygenation Cardiopulmonary bypass (CPB) tubing
  (ECMO) tubing                       
  ----------------------------------- -----------------------------------

In this section, an attempt is made to quantify the dose of DEHP
received by patients undergoing various medical procedures. In most
cases, exposure is represented as administered dose (mg/kg/day) and is
time-averaged over a course of treatment. For example, if an adult
patient receives 60 mg of DEHP in a hemodialysis session, and undergoes
hemodialysis three times per week, the time-averaged dose of DEHP
received by this patient would be 60 mg/session x 3 sessions/week x
week/7 days x 1/70 kg = 0.37 mg/kg/day. It is necessary to represent
exposure dose in units of mg/kg/day, time-averaged over the exposure
period, so a common dose metric exists for comparison of the dose of
DEHP received by patients and the dose of DEHP used in toxicity studies.
A summary of the estimated DEHP dose received by patients undergoing
various procedures is provided at the end of this section (Table A-24).

In addition to DEHP, patients can be exposed to the monoester of this
phthalate, MEHP. Since MEHP is thought to be the active metabolite
mediating many of the adverse effects of DEHP, it is important to assess
exposure to this compound as well.

**A.1 Parenteral Exposure to DEHP and MEHP**

Parenteral exposure to DEHP and MEHP can occur following intravenous
infusion of crystalloid solutions (e.g., normal saline, D5W, Ringers
Lactate) and drugs, administration of enteral nutrition and total
parenteral nutrition (TPN) solutions, and transfusion of blood or blood
products. In addition, patients undergoing cardiopulmonary bypass (CPB),
extracorporeal membrane oxygenation (ECMO), hemodialysis or peritoneal
dialysis can also be exposed to DEHP. The extent to which DEHP is
released from PVC medical devices is largely a function of the
lipophilicity of the fluid that comes into contact with the device.
Substances like blood, plasma, red blood cell or platelet concentrates;
IV lipid emulsion or total parenteral nutrition solution; and
formulation aids (e.g., Polysorbate 80) used to solubilize IV
medications can readily extract DEHP from PVC tubing and containers. In
contrast, nonlipid-containing fluids, like crystalloid IV solutions,
saline priming solution for ECMO and hemodialysis, and peritoneal
dialysis solution, extract relatively only small amounts of DEHP from
the PVC constituents of the device. Doses of DEHP administered to
patients undergoing each of these procedures are estimated below.

**A.1.1 Intravenous Solutions**

# A.1.1.1 DEHP dose following infusion of crystalloid solutions 

In the absence of lipid-containing substances, the amount of DEHP that
leaches from PVC storage bags into crystalloid IV solutions is generally
very small. For example, little or no DEHP was found to leach into
crystalloid solution (normal saline, D5W) stored in PVC bags for more
than one year (Dine et al., 1991). Similar findings were reported by
Moorhatch and Chiu (1974). Corley et al. (1977) quantified levels of
DEHP in various crystalloid IV solutions (normal saline, D5W, Ringers
Lactate) packaged in PVC bags as a function of administration time and
whether the bags were agitated or not. Agitation involved shaking for 24
hours at room temperature. The level of DEHP in nonagitated bags did not
increase as a function of administration time and ranged between 0.067
and 0.172 μg/ml, yielding a DEHP dose of 0.134 to 0.344 mg of DEHP/day
assuming infusion of 2 L of fluid/day. Agitation increases the
concentration DEHP in solution. These levels ranged from 0.43 to 2.87
μg/ml, yielding a DEHP dose to an adult patient receiving 2 L of IV
fluid/day of 0.86 to 5.74 mg/day.

Arbin and colleagues (Arbin et al., 1980; 1986) detected lower levels of
DEHP in D5W and normal saline than Corley et al. (1977) did. Levels
detected by Arbin et al. (1980) ranged from \< 0.004 to 0.034 μg/ml. At
these concentrations, an adult patient receiving 2 L of IV fluids/day
would receive up to 0.068 mg of DEHP.

The upper-bound value of DEHP in crystalloid IV solutions as reported by
Corley et al. (1977) for non-agitated bags (0.344 mg/day) was used to
develop the adult TI/Dose ratios for this procedure, since non-agitated
bags best represent the clinical situation and since this value
approximates the upper-bound solubility of DEHP in aqueous media. The
time-averaged dose of DEHP delivered to a 70 kg patient receiving 2 L of
IV solution/day would be on the order of 0.005 mg/kg/day.

Neonatal patients do not typically receive IV fluid administration via a
gravity feed, rather a syringe infusion pump is often used to administer
IV fluids to pediatric patients. Although the syringe used is typically
made from polypropylene, a small amount of DEHP can be released from the
PVC administration tubing. Loff et al. (2000) found that infusion of a
crystalloid IV solution through PVC tubing for 24 hours yielded a DEHP
dose of 116 μg, equivalent to a dose of 0.06 mg/kg/day for a 2 kg
neonate.

It is accepted practice in some facilities to warm IV solutions in a
microwave oven. Other facilities will use a blood warmer to increase the
temperature of IV fluids. Data are unavailable on the extent to which
heating a PVC bag will increase the concentration of DEHP in a
crystalloid solution; however, this practice could increase the dose of
DEHP to a patient receiving crystalloid solutions intravenously. It
should be noted however, that the use of a blood warmer is the more
accepted means of warming IV fluids. During this procedure, the infused
fluid is heated to about 40^o^C as it flows through the administration
tubing into the patient. As a result, the PVC bag itself is not heated
during this procedure and the heated infusate does not enter the PVC
bag.

**A.1.1.2 DEHP dose following infusion of crystalloid solutions
containing lipophilic drugs dissolved in pharmaceutical solvents**

The package insert labeling that accompanies a number of drug products,
notably antineoplastics, caution against the use of PVC containers for
storage and delivery of the drug. If non-PVC containers and non-PVC
infusion sets are used to administer the drug, DEHP exposure is expected
to be minimal.

**Table A-2. Drug Products that Include Labeling Precautions for the Use
of PVC Containers**

  ----------------------------------- -----------------------------------
  [Generic Name]{.underline}          [Trade Name]{.underline}

                                      

  Paclitaxel                          Taxol (Bristol-Myers Squibb

  Docetaxel                           Taxotere (Rhone-Poulenc Rorer)

  Tacrolimus                          Prograf (Fujisawa)

  Teniposide                          Vumon (Bristol-Myers Squibb)
  ----------------------------------- -----------------------------------

Faouzi et al. (1999a) found that 52 mg of DEHP were released into
intravenous solution when teniposide was stored in PVC bags for 48 hours
at room temperature. A 70 kg patient receiving teniposide stored under
these conditions would receive a time-averaged DEHP dose of 0.74
mg/kg/day. When the bags were stored at 19^o^C, 19 mg of DEHP was
released. Since the manufacturer suggests that this drug be
reconstituted just prior to administration, and since DEHP concentration
in teniposide solution increases as a function of storage time (Faouzi
et al., 1999a), considerably less DEHP would be expected to be infused
into a patient under standard administration practices. Faouzi et al.
(1999a) provided data from a simulated infusion that permit a more
accurate estimate of DEHP dose to be made. These investigators prepared
teniposide (400 μg/ml) in 250 ml of 5% dextrose solution in PVC bags and
conducted a simulated infusion using PVC tubing. Data were then provided
on the concentration of DEHP in solution taken from the bag and from the
infusion set during a one-hour infusion. Since the data were reported in
a figure, the concentration of DEHP infused was obtained by estimating
the concentration off the graph and manually integrating the data. Using
this approach, it appears that about 2 mg of DEHP could be infused into
a patient based on these data. DEHP released from the PVC administration
set contributes significantly to the total DEHP dose, especially in the
early time periods (i.e., during the first 30 minutes of the infusion).
Based on the difference between the concentration of DEHP in solution
sampled from the bag and from the administration set, integrated over
the duration of the infusion, it appears that the administration set
contributed about 0.84 mg of the total 2 mg dose of DEHP that could be
administered during the infusion period.

***DEHP dose following drug infusion from "low DEHP" bags***

The labeling information provided with a number of drugs instructs the
user to administer and store the reconstituted drug in PVC bags that
release minimal amounts of DEHP, such as Baxter's PL-146 bag. The
concentration of DEHP in these bags is assumed to not exceed 5 ppm (5
μg/ml). Table A-3 provides a worst case estimate of the dose of DEHP
received by patients receiving these assuming that the drugs are
premixed in PL-146 IV bags and the premixed solution is agitated for 24
hours at room temperature before administration to the patient.

##### Table A-3. Dose of DEHP Received Following Administration of Various Drug Products

+-----------------------+-----------------------+-----------------------+
| **Generic Name**      | **Trade Name**        | **DEHP Dose**         |
|                       |                       |                       |
|                       |                       | **(mg/day)**          |
+-----------------------+-----------------------+-----------------------+
| Ciprofloxacin         | Cipro IV (Bayer)      | 1.0 -- 3.0            |
+-----------------------+-----------------------+-----------------------+
| Cefoperazone sodium   | Cefobid Bulk (Pfizer) | 0.5                   |
+-----------------------+-----------------------+-----------------------+
| Fluconazole           | Diflucan (Pfizer)     | 1.0                   |
+-----------------------+-----------------------+-----------------------+
| Metronidazole HCl     | Flagyl IV (SCS)       | 0.5                   |
+-----------------------+-----------------------+-----------------------+
| Cimetidine            | Tagamet (SmithKline   | 0.75                  |
|                       | Beecham)              |                       |
+-----------------------+-----------------------+-----------------------+

An explanation of how these estimated doses were derived is provided
below.

######### Ciprofloxacin

The labeling information for Cipro® IV (ciprofloxacin) points out that
DEHP can leach from the PVC container used to store and deliver this
drug at a concentration up 5 parts per million (ppm). To estimate the
dose of DEHP received by patients being administered this drug,
information is needed on the volume of solution containing the drug and
the frequency with which it is administered. For mild urinary tract
infections, the recommended dose of ciprofloxacin is 200 mg every 12
hours (PDR, 1998). The drug comes packaged in a flexible PVC container
that contains 200 mg in 100 ml of solution. If the concentration of DEHP
in solution is 5 ppm or 5 mg/L, the dose of DEHP received by a patient
receiving this drug to treat a urinary tract infection would be:

5 mg DEHP/L x 100 ml/administration x 2 administrations/day x 0.001 L/ml
= 1 mg DEHP/day.

More aggressive treatment is required to treat more severe infections.
For example, a dose of 400 mg of ciprofloxacin is recommended every 8
hours to treat severe infections of the respiratory tract, bones,
joints, or skin. The dose of DEHP received in this dosing regimen would
be:

5 mg DEHP/L x 200 ml/administration x 3 administrations/day x 0.001 L/ml
= 3 mg DEHP/day.

######### Cefoperazone Na

Cefoperazone Na (Cefobid Bulk) is available in 1 or 2 g amounts premixed
in 50 ml PVC bags to be used as piggyback units. The usual dose is A-4
g/day divided every 12 hours (PDR, 1999). Therefore, administration
every 12 hours would yield a DEHP dose of

50 ml/bag x 0.005 mg DEHP/ml x 2 bags/day = 0.5 mg/day.

This dose not include any DEHP released from a PVC administration set.
Cefobid Bulk is also available premixed in polyethylene bags (PL-2040).
Use of drug stored in PL-2040 bags would result in DEHP exposure from
the infusion set only.

####### ***Fluconazole***

Fluconazole (Diflucan) is available as a premixed solution Viaflex
(PL-146) bags. The concentration of Diflucan in the premixed solution is
200 mg in 100 ml or 400 mg in 200 ml (PDR, 1999). The total maximum dose
of Diflucan is 400 mg/day. The amount of DEHP expected to be
administered with this dose is:

200 ml/day x 0.005 mg DEHP/ml = 1 mg DEHP/day.

######### Metronidazole HCl

Metronidazole HCl (Flagyl IV) is available premixed in PL-146 bags
containing 500 mg of drug. The loading dose of Flagyl IV is 1 g in the
first hour, followed by the maintenance dose of 500 mg every 6 hours.
Therefore in the first day, a patient could receive six bags of premixed
solution. Assuming a DEHP concentration of 5 ppm, the dose of DEHP
received by patients treated with Flagyl IV would be:

100 ml/bag x 6 bags/day x 0.005 mg DEHP/ml = 3 mg DEHP/day

#### Cimetidine

Cimetidine (Tagamet) is available in single dose premixed PVC
containers. Each 50-ml bag contains 300 mg of drug. The recommended
dosage of Tagamet is 300 mg every four hours. This dosing regimen would
result in a maximal DEHP dose of:

50 ml/bag x 4 bags/day x 0.005 mg/ml = 1 mg/day

Again, this estimate does not include the potential contribution of DEHP
released from the administration set to the total dose received by the
patient.

Concern has been expressed about the dose of DEHP received following
infusion of certain lipophilic drugs, notably, several antineoplastic
drugs. However, as discussed in Section A.1.1.2 (above), relatively
small amounts of DEHP are released from these bags if the drugs are
prepared according to the manufacturer's instructions. However,
premixing and storage of these drugs in PVC bags at room temperature can
result in a considerably higher dose of DEHP being delivered to a
patient (e.g. 52 mg/bag as shown by Fauozi et al, 1999). The upper-bound
dose DEHP received following administration of drugs prepared in PL-146
bags is on the order of A-3 mg/day or about 0.03 to 0.05 mg/kg/day for a
70 kg adult.

######### DEHP dose following drug infusion from non-PVC bags

In addition to "low DEHP" PL-146 bags, non-PVC bags are also available
for the administration of drugs that require a lipophilic vehicle for
solubilization. No DEHP is expected to be released from non-PVC bags
(however, some DEHP may be released from a PVC administration set if one
is used). Consistent with this expectation, Sautou-Miranda et al. (1999)
demonstrated that no DEHP was detected in a solution of paclitaxel
stored in a polyethylene container for 15 days.

***Drug infusions in pediatric patients***

Drug infusions are typically administered to pediatric patients using an
infusion pump. Loff et al. (2000) measured the amount of DEHP that could
be received by a pediatric patient receiving IV drug therapy (Table
A-4).

**Table A-4. Dose of DEHP received by neonates undergoing IV drug
therapy (Loff et al., 2000)**

+-----------+-----------+-----------+-----------+-----------+-----------+
| Drug      | Perfusion | Conc      | Amount in | Total     | Total     |
|           | time      | entration | ml        | Amount of | Dose of   |
|           | (hours)   |           |           | DEHP (μg) | DEHP      |
|           |           | of DEHP   |           |           | (m        |
|           |           | after     |           |           | g/kg/day) |
|           |           | perfusion |           |           | for a 2   |
|           |           | (μg/ml)   |           |           | kg        |
|           |           |           |           |           | neonate   |
+-----------+-----------+-----------+-----------+-----------+-----------+
| Imipenem  | 0.5       | 0.78      | 8         | 6.26      | 0.003     |
+-----------+-----------+-----------+-----------+-----------+-----------+
| Midazolam | 24        | 1.13      | 24        | 26.4      | 0.013     |
+-----------+-----------+-----------+-----------+-----------+-----------+
| Fentanyl  | 24        | 4.59      | 29        | 132.5     | 0.066     |
+-----------+-----------+-----------+-----------+-----------+-----------+
| Propofol  | 24        | 656       | 10        | 6561      | 3.28      |
+-----------+-----------+-----------+-----------+-----------+-----------+

As shown in Table A-4, relatively little DEHP is expected to be received
by children undergoing drug therapy with imipenem, midazolam or
fentanyl. In contrast, patients receiving propofol can receive a
considerable dose of DEHP over a 24 hour period. However, propofol is
not approved for sedation in pediatric ICU patients in the US (FDA,
2001), therefore, the upper-bound dose of DEHP received by neonates
undergoing conscious sedation is on the order of 0.07 mg/kg/day for a 2
kg infant.

***Multiple Drug Infusions***

Often, multiple drugs are co-infused in the same IV infusion. One such
case is the co-infusion of quinine along with multivitamin preparations.
Faouzi et al. (1999b) demonstrated little DEHP is released from PVC bags
containing quinine alone in solution; however, the presence of the
lipophilic multivitamin cocktail dramatically increased the extent of
DEHP release from the bag. Following storage of quinine/multivitamin
combinations for 48 hours at 45^o^C, the concentration of DEHP in the
bags reached 21 μg/ml. Consequently, a patient receiving a 500 ml
infusion of quinine with a multivitamin cocktail would receive 10.8 mg
of DEHP.

# A.1.1.3 Exposure to compounds other than DEHP in intravenous infusion solutions

Exposure of patients to MEHP is addressed in Annex C. In addition to
MEHP, Arbin et al. (1986) identified a number of contaminants in normal
saline solutions stored in PVC bags using GC-MS or gradient liquid
chromatography (LC) techniques. Levels of these contaminants in IV
solutions stored for about 1 year in 100-ml bags from either ACO
Lakemedel AB or Travenol are shown in Table A-5.

**Table A-5. Contaminants identified in normal saline stored for 1 year
in PVC bags (Arbin et al., 1986)**

  ----------------------- ----------------------- -----------------------
  Contaminant             Concentration (μg/ml)   

                                                  

                          ACO bag                 Travenol bag

                                                  

  Phthalic acid           0.026                   0.027

  Cyclohexanone           \-                      35.00

  Phenol                  0.024                   0.029

  Phthalide               0.016                   0.580

  Benzoic acid            0.029                   \-

  Benzaldehyde            0.005                   0.013

  Bisphenol-A             \-                      0.320

  Butyl hydroxyanisol     0.058                   \-

  MEHP                    0.454                   \-

  DEHP                    0.007                   0.005

                                                  
  ----------------------- ----------------------- -----------------------

A number of other compounds (i.e., acrolein, tetrahydrofuran, toluene,
xylene) were identified using dynamic headspace GC-MS analysis following
heating of the bag to 120^o^C for 5-20 minutes; however, appearance of
these compounds in the infusion solution is dependent on the partition
coefficient of the compound between the bag and the solution.

# A.1.1.4. Phthalate ester exposure from non-PVC Bags containing drug solutions

Trilaminate bags (outside-polypropylene, middle-nylon,
inside-polyethylene) serve as an alternative to PVC bags for the
administration of IV drugs that require pharmaceutical vehicles for
solubilization. However, Sarbach et al. (1996) found that higher levels
of phthalate (presumably, DEHP) were being released from a trilaminate
IV bag into aqueous solution containing 0.5% metronidazole than were
released from Baxter\'s Viaflex bag into saline. The trilaminate bag has
been marketed under the trade name, Clear-Flex. Levels of phthalate in
solution contained in the trilaminate bag ranged from 128 to 149 ug/100
ml. Levels of DEHP in saline contained in the non-agitated Viaflex PVC
bag ranged from 0.53 to 0.77 ug/100 ml. By extracting each of the layers
of the bag separately, and by analyzing the polyurethane cement used to
manufacture the bag, the investigators found that the phthalate came
from the polyurethane cement. It is important to point out that the
compound identified by Sarbach et al. (1996) may not be DEHP, since a
mass spectrum of the chromatogram peak simply indicated a "phthalate
structure". Structural proof by other means (e.g., IR, NMR) was not
accomplished to demonstrate that the compound represented by the peak
was indeed DEHP. Phthalate anhydride is sometimes used as a curing agent
for ester type adhesive which the polyurethane is likely to contain.
Phthalate anhydride in water hydrolyzes to phthalic acid, which may be
the phthalate structure that Sarbach et al. (1996) observed. Unique
identification of the phthalate structure found by Sarbach et al. (1996)
is necessary before conclusions can be made about the presence of DEHP
in solutions stored in trilaminate bags

### A.1.2 Parenteral Nutrition

Total parenteral nutrition (TPN) formulations are often administered to
critically ill patients requiring nutritional supplementation.
Parenteral administration involves infusion directly into the
circulatory system. Typical TPN admixtures contain amino acids,
dextrose, electrolytes and lipids. Mazur et al. (1989) have shown that
the presence of lipid in the TPN solution increases the concentration of
DEHP in the admixture when PVC bags are used. The concentration of DEHP
in TPN formulations without added lipid are below the limit of
detection. The concentration of DEHP in the TPN solution increases as a
function of time and storage temperature. Table A-6 lists the daily dose
(mg/day) received by a patient receiving 3 L of TPN admixture that is
either lipid-free or that has a lipid concentration of either 10% or
20%.

##### Table A-6. Dose of DEHP (mg/day) following administration of 3L of TPN admixture (adapted from Mazur et al., 1989)

  ----------------- ----------------- ----------------- -----------------
  Days of storage   Dose of DEHP                        
                    (mg/day)                            
                    following                           
                    administration of                   
                    3L of TPN                           

                    Without addition  with addition of  with addition of
                    of lipid emulsion 10% lipid         20% lipid
                                      emulsion          emulsion

                                                        

  1                 0.3               0                 0

                                                        

  2                 2.1               9.3               7.8
  ----------------- ----------------- ----------------- -----------------

As shown in Table A-6, the dose of DEHP received by a patient increases
as a function of storage time. According to Mazur et al. (1989), TPN
solutions are administered within 24 to 36 hours of admixture. During
this period, the maximal concentration of DEHP measured in TPN solution
by Mazur et al. (1989) was 3.1 µg/ml. The resulting upper-bound dose of
DEHP received by a patient following storage of the TPN solution for 48
hours would be 9.3 mg, when all 3 L of TPN solution is infused. However,
administration of unrefrigerated TPN solution within 24 hours of
admixture is unlikely to deliver more than 3 mg of DEHP.

The results of Mazur et al. (1989) are not consistent with those of
Allwood (1986). Following storage of a TPN admixture with 20% Intralipid
for 24 hours, the concentration of DEHP in the TPN solution was 40
μg/ml. Infusion of 2.5 L of this admixture into a patient would result
in a dose of 100 mg of DEHP. The dose of DEHP received following
infusion of 10% or 20% Intralipid alone, 20% Intralipid with TPN or TPN
without Intralipid is shown in Table A-7.

##### Table A-7. Dose of DEHP (mg/day) following administration of 2.5 L of TPN admixture following 24 hours of storage (adapted from Allwood, 1986)

  --------------------- ------------------------ -------------------------
  TPN Preparation       Dose of DEHP (mg/day)    
                        following administration 
                        of 2.5 L of TPN          

                        Stored at 4-6^o^C        Stored at ambient
                                                 temperature

  10% Intralipid        35                       80

  20% Intralipid        32                       72

  TPN (2L) with 20%                              100
  Intralipid (0.5L)                              

  TPN without                                    3.75
  Intralipid                                     
  --------------------- ------------------------ -------------------------

Allwood (1986) also conducted a simulated infusion without storage to
estimate the dose of DEHP received by a patient receiving Intralipid.
The results of this study indicate that a patient receiving 500 ml of
10% Intralipid would receive about 2.5 to 2.75 mg of DEHP and a patient
receiving 20% Intralipid would receive about 1.5 mg/day.

***DEHP dose from PVC administration sets used to administer TPN***

Although PVC storage bags are still used for TPN administration, EVA
(ethylvinyl acetate) bags are being increasingly used for this
application. However, even EVA bags contain PVC components (Kambia et
al., 2001), resulting in the release of some DEHP into the TPN solution.
In addition, although plasticizer-free tubing can be used gravity
infusion of lipid emulsions, the use of PVC tubing is required for pump
assisted lipid administration. Pump-assisted administration is necessary
to overcome hyperalimentation fluid-lipid density differences and
variable central venous back pressures. Further, PVC tubing and infusion
pumps are always used to administer lipids to pediatric and neonatal
patients. Therefore, it is possible that a significant amount of DEHP
could be received by patients receiving TPN even though non-PVC bags are
used to store the TPN solution.

The amount of DEHP released into TPN solution stored for 24 hours in EVA
bags ranged from 0.2 to 0.7 mg (Kambia et al., 2001); 0.8 to 2 mg was
released from the bag and the PVC administration set, following flow of
the emulsion through the tubing for 11 hours. Assuming the highest
amount of DEHP released from the outlet of the tubing came from
emulsions containing the highest concentrations of DEHP, then the amount
of DEHP released from the tubing ranged from 0.6 to 1.3 mg/day, based on
administration for 11 hours/day. Based on these values, up to 2.8 mg of
DEHP could presumably be released from the tubing over a 24-hour
infusion and up to 4.4 mg of DEHP total (EVA bag + tubing) could be
received over a 24-hour period.

Unlike adults or even older children, neonates typically receive TPN via
a syringe infuser. Loff et al. (2000) recently reported that if PVC
tubing is used to administer the TPN, an infant could receive over 10 mg
of DEHP from the tubing over a 24-hour period (equivalent to 2.5
mg/kg/day for a 4 kg neonate). However, an upper-bound dose of DEHP
received by neonates can also be derived from the data reported by
Kambia et al. (2001) as follows: 1600 ng/ml (maximum conc. of DEHP
measured at outlet of PVC tubing) x 150 ml/kg/day (upper-bound dose rate
for administration of TPN to neonates) = 0.24 mg/kg/day.

Wide differences exist in estimated daily dose of DEHP following
administration of lipid-containing TPN exist depending on whether data
from the Mazur et al. (1989) or Allwood (1986) are used to derive the
dose estimate. Also the dose will vary depending on the material used to
manufacture the storage bag (DEHP-plasticized PVC, non-DEHP plasticized
PVC, or polyolefin) and whether a PVC infusion set is used. In Table
A-24, the estimated dose of DEHP received by a 70 kg adult receiving a
lipid containing TPN solution (0.08 mg/kg/day) comes from the assumption
that 2.8 mg of DEHP can be released from PVC tubing per day (based on
data provided by Kambia et al., 2001) and 3.0 mg of DEHP can partition
from the PVC bag into TPN solution (based on the data of Mazur et al.,
1989, assuming administration of unrefrigerated TPN within 24 hours).
However, an estimated DEHP dose of 2.1 mg/kg/day for adults receiving
TPN can be derived from the data reported by Allwood (1986) and
Easterling et al (1974).

### A.1.3 Transfusion of blood and blood products

DEHP migrates from PVC storage bags and into blood and blood products
(platelets, plasma, packed red blood cells) because of the lipophilic
nature of these biological fluids and cells. The concentration of DEHP
reported in blood or blood products is summarized in Table A-8.

##### Table A-8. Concentration of DEHP in Blood and Blood Products

+-------------------+----------------+--------------+-----------------+
| **Blood Product** | **DEHP         | **DEHP       | **Study**       |
|                   | c              | con          |                 |
|                   | oncentration** | centration** |                 |
|                   |                |              |                 |
|                   | **Mean**       | **Range**    |                 |
|                   |                |              |                 |
|                   | **(μg/ml)**    | **(μg/ml)**  |                 |
+-------------------+----------------+--------------+-----------------+
|                   |                |              |                 |
+-------------------+----------------+--------------+-----------------+
| Plasma            | 44.8           | 4.3 to 123.1 | Plonait et al.  |
|                   |                |              | (1993)          |
+-------------------+----------------+--------------+-----------------+
| Plasma            | 54.6           | 36.8 to 84.9 | Sjoberg et al.  |
|                   |                |              | (1985)          |
+-------------------+----------------+--------------+-----------------+
| Plasma            | 38.0           | 13.8 to 71.9 | Sjoberg et al.  |
|                   |                |              | (1985)          |
+-------------------+----------------+--------------+-----------------+
| Plasma            |                | 363 to 545   | Dine et al.     |
|                   |                |              | (1991)          |
+-------------------+----------------+--------------+-----------------+
| Plasma            |                | \<110        | Vessman and     |
|                   |                |              | Reitz (1974)    |
+-------------------+----------------+--------------+-----------------+
| Plasma            |                | 100-275      | Vessman and     |
|                   |                |              | Reitz (1974)    |
+-------------------+----------------+--------------+-----------------+
| Plasma            |                | \<890        | Vessman and     |
|                   |                |              | Reitz (1974)    |
+-------------------+----------------+--------------+-----------------+
| Plasma            | 72.5           |              | Shintani et al. |
|                   |                |              | (1985)          |
+-------------------+----------------+--------------+-----------------+
| Plasma            | 172.6          |              | Shintani et al. |
|                   |                |              | (1985)          |
+-------------------+----------------+--------------+-----------------+
| Plasma            | 266            |              | Cole et al.     |
|                   |                |              | (1981)          |
+-------------------+----------------+--------------+-----------------+
| Plasma            | 145            | 106 to 209   | Marcel (1973)   |
+-------------------+----------------+--------------+-----------------+
| Plasma            |                | 290 to 1230  | Contreras et    |
|                   |                |              | al. (1974)      |
+-------------------+----------------+--------------+-----------------+
| Platelet- rich    | 181            |              | Rock et al.     |
| plasma            |                |              | (1978)          |
+-------------------+----------------+--------------+-----------------+
| Platelet-poor     | 285            |              | Rock et al.     |
| plasma            |                |              | (1978)          |
+-------------------+----------------+--------------+-----------------+
| Leucocyte-poor    |                | 25-32        | Piechocki and   |
| plasma            |                |              | Purdy (1973)    |
+-------------------+----------------+--------------+-----------------+
| Fresh frozen      |                | 11.2 - 339   | Loff et al.     |
| plasma            |                |              | (2000)          |
+-------------------+----------------+--------------+-----------------+
| Fresh frozen      | 26.7           |              | Shintani et al. |
| plasma            |                |              | (1985)          |
+-------------------+----------------+--------------+-----------------+
| Fresh frozen      | 12             |              | Cole et al.     |
| plasma            |                |              | (1981)          |
+-------------------+----------------+--------------+-----------------+
| Whole blood       | 52.5           |              | Jaeger and      |
|                   |                |              | Rubin (1972)    |
+-------------------+----------------+--------------+-----------------+
| Whole blood       |                | 140 to 620   | Contreras et    |
|                   |                |              | al. (1974)      |
+-------------------+----------------+--------------+-----------------+
| Whole blood       | 152.5          |              | Peck et al.     |
|                   |                |              | (1979)          |
+-------------------+----------------+--------------+-----------------+
| Whole blood       | 123.4          |              | Peck et al.     |
|                   |                |              | (1979)          |
+-------------------+----------------+--------------+-----------------+
| Platelet          | 267.0          |              | Shintani et al. |
| concentrate       |                |              | (1985)          |
+-------------------+----------------+--------------+-----------------+
| Platelet          | 491            |              | Rock et al.     |
| concentrate       |                |              | (1978)          |
+-------------------+----------------+--------------+-----------------+
| Platelet          |                | 23.4 to 48.8 | Loff et al.     |
| concentrate       |                |              | (2000)          |
+-------------------+----------------+--------------+-----------------+
| Red cell          | 54.6           | 36.8 to 84.9 | Sjoberg et al   |
| concentrate       |                |              | (1985a,b)       |
+-------------------+----------------+--------------+-----------------+
| Red cell          | 44.8           | 4.3 to 123.1 | Plonait et al.  |
| concentrate       |                |              | (1993)          |
+-------------------+----------------+--------------+-----------------+
| Red cell          |                | 7.2 to 30.4  | Loff et al.     |
| concentrate       |                |              | (2000)          |
+-------------------+----------------+--------------+-----------------+
| Red cell          | 152            |              | Peck et al.     |
| concentrate       |                |              | (1979)          |
+-------------------+----------------+--------------+-----------------+

The values listed in Table A-8 illustrate the variability in
measurements of DEHP in blood and blood products. The variability can be
explained somewhat by factors such as differences in the duration of
storage and storage conditions (i.e. temperature), use of various
analytical techniques, and differences in levels of lipids in the blood
and plasma.

To derive appropriately protective TI/Dose ratios (see Section 4.0),
upper-bound concentrations of DEHP will be used to derive administered
dose estimates (below). Current clinical practices in transfusion
medicine have been taken into account in deriving these administered
dose estimates. For example, whole blood is rarely administered
clinically. Instead, patients usually receive RBCs, platelets, fresh
frozen plasma (FFP) or some combination of these products. Estimates are
provided below of levels of DEHP in each type of blood product.

######### Concentration of DEHP in packed RBC

Levels of DEHP in serum from red cell concentrates prepared for exchange
transfusion ranged from 4.3 to 123.1 μg/ml, with a mean of 44.8 μg/ml
(Plonait et al., 1993) The upper-bound value from this study is
consistent with that reported by Peck et al. (1979). Assuming a volume
of about 350 ml/unit of RBCs (McCullough, 1998), each unit of red cell
concentrate would be expected to deliver a DEHP dose of 43.1 mg, using
the upper-bound concentration (123.1 μg/ml) from the Plonait et al.
(1993) study.

######### Concentration of DEHP in FFP

Another trend that reflects current clinical practice is the use of
fresh frozen plasma (FFP) instead of unfrozen, stored plasma. Levels of
DEHP in FFP appear to be lower than those measured in unfrozen plasma.
Requirements for the preparation of fresh frozen plasma specify that the
plasma should be separated from RBCs within 8 hours of storage of the
whole blood, then frozen at --18^o^C. Since amount of DEHP released from
PVC changes as a function of temperature, it is not surprising that less
DEHP is released into FFP than plasma stored at higher temperatures. To
reflect current practice, data on levels of DEHP in FFP will be used to
estimate patient exposure to this phthalate ester instead of levels in
unfrozen plasma. Also, since platelets are commonly stored in non-PVC
bags, it is assumed that exposure to DEHP in patients receiving
platelets will occur as a result of DEHP leaching from the blood
administration set, if a PVC infusion set is used to administer the
platelets.

# Dose of DEHP received following the transfusion of blood or blood products

When estimating the dose of DEHP received by patients receiving blood or
blood products, it is important to differentiate between two
scenarios: 1) infusion of large amounts of blood or blood products over
a short period and 2) chronic infusion of smaller volumes of blood over
a prolonged period. Acute, large-volume blood transfusion is necessary
in the treatment of acute blood loss in trauma patients, some patients
undergoing surgery, patients with acute gastrointestinal bleeding and
neonates undergoing exchange transfusion. Chronic administration of
smaller volumes of blood or blood products is common in the treatment of
patients with chemotherapy-associated anemia, blood disorders such as
leukemia and aplastic anemia, and in the treatment of patients with
clotting disorders.

### *Short-term blood transfusion*

Short-term blood transfusion scenarios include large volume transfusions
of blood and blood products to trauma patients, patients with
gastrointestinal bleeding, and patients undergoing ECMO, as well
replacement transfusions for infants in neonatal intensive care units
(NICUs) and adult undergoing surgical procedures.

######### Large volume replacement in adults

Based on the results reported by other investigators, Sjoberg et al.
(1985b) estimated that an adult receiving 2.5 L of blood stored for 21
days would receive a DEHP dose of 1.3 to 2.6 mg/kg. In cases of massive
blood loss and transfusion of large amounts of blood, considerably more
DEHP could be administered to a patient. For example, Jaeger and Rubin
(1972) estimated that a gunshot victim receiving 63 units of blood would
receive a DEHP dose of around 8.5 mg/kg. The concentration of DEHP in
the blood of this patient was 2.8 μg/ml.

Although it is possible for trauma patients to receive \> 50 units of
blood or blood products (Hakala et al., 1999), similar to the patient in
the scenario described by Jaeger and Rubin (1972), the typical
transfusion volume in trauma patients is much less. Farion et al. (1998)
reported that a mean of 3.57 units of packed cells was transfused into
seriously injured adults and that there has been a decrease in blood
product use in the management of these patients. Consequently, use of a
DEHP dose derived on the basis of a 63 unit transfusion represents a
worst case scenario with regard to DEHP exposure via transfusion.
Patients undergoing routine, elective surgical procedures typically
receive about two units of blood or blood products (Mallett et al.,
2000). Assuming a mean DEHP concentration of 44.8 μg/ml for packed cells
(Plonait et al., 1993) and a packed cell volume of 350 ml, transfusion
in a typical surgery would result in administration of a DEHP dose of
0.5 mg/kg/day.

As discussed in Section A.1.3.2, patients undergoing ECMO are exposed to
relatively large amounts of DEHP. In addition to DEHP released from PVC
tubing used in the ECMO device, it is also important to account for DEHP
exposure from blood transfusions given to these patients. Patients on
ECMO receive RBCs to correct anemia and they receive platelet
concentrates, FFP, and cryoprecipitate to treat clotting disorders. As
shown in Table A-9, it is possible for adult patients to receive over
600 units of blood products during the course of their ECMO treatment
and hospitalization. Daily use of blood components in adult patients
undergoing ECMO is shown in Table A-10.

**Table A-9. Blood component utilization in adult patients during
hospitalization and while undergoing ECMO (Median utilization/patient)
(Butch et al., 1996)**

  ----------------- ----------------- ----------------- -----------------
  **Blood product** **Median units                      
                    transfused**                        

                    **In hospital**   **During ECMO**   **Range**

                                                        

  RBCs              45.0              28.5              0-181

  Platelet          112.5             108.0             0-682
  concentrates                                          

  FFP               7.0               2.0               0-99

  Cryoprecipitate   3.0               2.0               0-240

                                                        
  ----------------- ----------------- ----------------- -----------------

**Table A-10. Daily blood component utilization in adult patients
undergoing ECMO (Butch et al., 1996)**

  ----------------- ----------------- ----------------- -----------------
  **Blood product** **Units                             
                    transfused**                        

                    **Mean**          **Median**        **Range**

                                                        

  RBCs              4.6               3.2               0-18

  Platelet          15.0              13.6              0-18
  concentrates                                          

  FFP               0.5               0.3               0-2.5

  Cryoprecipitate   1.0               0.1               0.8.9

                                                        
  ----------------- ----------------- ----------------- -----------------

The values listed in Table A-9 and A-10 underscore the massive amounts
of blood products required by adult patients undergoing ECMO. The dose
of DEHP received during these transfusions is estimated in Table A-11.

##### Table A-11. Dose of DEHP received from transfusion in adult patients undergoing ECMO 

+---------------+--------------+------------+-------------+---+-----------+
| **Blood       | **Number of  | **Vol      | **Estimated |   | **DEHP    |
| product**     | units        | ume/unit** | DEHP        |   | dose^1^** |
|               | tr           |            | co          |   |           |
|               | ansfused/day | **(ml)**   | ncentration |   | **(mg/    |
|               | (mean)**     |            | (μg/ml)**   |   | kg/day)** |
+---------------+--------------+------------+-------------+---+-----------+
|               |              |            |             |   |           |
+---------------+--------------+------------+-------------+---+-----------+
| RBCs          | 4.6          | 350        | 123.1       | 2 |           |
|               |              |            |             | . |           |
|               |              |            |             | 8 |           |
+---------------+--------------+------------+-------------+---+-----------+
| Platelet      | 15.0         | 100        | 5.6         | 0 |           |
| concentrates  |              |            |             | . |           |
|               |              |            |             | 1 |           |
|               |              |            |             | 2 |           |
+---------------+--------------+------------+-------------+---+-----------+
| FFP           | 0.5          | 200        | 26.7        | 0 |           |
|               |              |            |             | . |           |
|               |              |            |             | 0 |           |
|               |              |            |             | 4 |           |
+---------------+--------------+------------+-------------+---+-----------+
| Cr            | 1.0          | 50         | 1.0         | 0 |           |
| yoprecipitate |              |            |             | . |           |
|               |              |            |             | 0 |           |
|               |              |            |             | 0 |           |
|               |              |            |             | 0 |           |
|               |              |            |             | 7 |           |
+---------------+--------------+------------+-------------+---+-----------+
|               |              |            |             |   |           |
+---------------+--------------+------------+-------------+---+-----------+

^1^Assumes 70 kg BW

The total dose of DEHP received each day from the blood products used in
ECMO for adults is on the order of 3.0 mg/kg/day. The amount of DEHP
extracted from blood administration sets should be added to this total.
Easterling et al. (1974) found that 4.45 to 10.2 mg of DEHP was
extracted from PVC tubing following perfusion of plasma through the
tubing for 5 hours. Assuming it takes 30 minutes to hour to infuse one
unit of packed RBCs, platelets, or FFP, the tubing would be expected to
contribute an additional 1 mg of DEHP to the total administered dose
during transfusion of each unit of blood products. Therefore, the total
amount of DEHP from the blood products and the infusion set would be 21
mg/day or 0.3 mg/kg/day for a 70 kg adult. This total should be added to
the amount of DEHP released from the PVC tubing used in the ECMO device
to estimate the total DEHP exposure of adults receiving ECMO. Therefore,
the total dose of DEHP received by adult patients being transfused
during ECMO treatment is on the order of 3.3 mg/kg/day. Since mean
values for the number of units transfused were used to calculate total
DEHP dose, the amount of DEHP received by some patients could be
considerable greater.

######### Exchange transfusion in neonates

Infants receiving exchange transfusion could receive a DEHP dose up to
22.6 mg/kg, according to Plonait et al. (1993); however, the DEHP dose
received by infants in the Sjoberg et al. (1985a,b) studies ranges from
0.84 to 4.22 mg/kg.

**Table A-12 Dose (mg/kg) of DEHP received by neonates at the end of
exchange transfusion**

  -------------- -------------- -------------- -------------- --------------
  **DEHP Dose                   **MEHP dose                   **Study**
  (mg/kg)**                     (mg/kg)**                     

  Mean           Range          Mean           Range          

                                                              

  1.77           0.84 to 3.30   0.10           0.04 to 0.20   Sjoberg et al.
                                                              (1985a)

  2.95           1.71 to 4.22   0.36           0.16 to 0.68   Sjoberg et al.
                                                              (1985b)

                 1.2 to 22.6                                  Plonait et al.
                                                              (1993)
  -------------- -------------- -------------- -------------- --------------

Since blood was sampled from the infusion set, there is no need to
account to the dose of DEHP leached from the tubing separately.

Sjoberg et al. (1985a,b) and Plonait et al. (1993) also measured levels
of DEHP in the postexchange serum of neonates that had been recently
transfused. These values are presented in Table A-13.

**Table A-13 Concentration (μg/ml) of DEHP and MEHP in serum obtained
from neonates at the end of a single exchange transfusion**

  --------------- -------------- --------------- -------------- --------------
  **DEHP                         **MEHP                         **Study**
  concentration                  concentration                  
  (μg/ml)**                      (μg/ml)**                      

  Mean            Range          Mean            Range          

                                                                

  \-              5.8 to 19.6    \-              5 (max)        Sjoberg et al.
                                                                (1985a)

  7.8             3.4 to 19.9    6.4             1.5 to 15.6    Sjoberg et al.
                                                                (1985b)

  14.5            6.1 to 21.6    \-              \-             Plonait et al.
                                                                (1993)

                                                                
  --------------- -------------- --------------- -------------- --------------

Slightly higher DEHP concentrations have been measured inpatients
receiving platelet concentrates. Rubin and Schiffer (1976) reported
plasma DEHP levels from 0.34 to 0.83 mg/dl (34 to 83 μg/ml) at
termination of the transfusion platelets that had been stored for up to
26 hours in vinyl plastic bags. Since platelets are no longer stored in
PVC bags, the values reported by Rubin and Schiffer (1976) most likely
overestimate the DEHP concentration in patients currently receiving
platelet transfusions.

######### Replacement transfusion in neonates in a NICU setting

Critically ill neonates require repeated phlebotomies that may deplete
their blood volume. Also, infants are susceptible to anemia of
prematurity. As a result, critically ill neonates often require
transfusions. Levy et al. (1993) reported that 80% of low birthweight
infants in the United States will receive multiple transfusions. Ringer
et al. (1998) reported that neonates in one neonatal intensive care unit
(NICU) received, on average, 33.6 ml of RBCs and 2.4 ml of FFP in the
first 14 days. Infants in this study weighed about 1 kg. The dose of
DEHP received by neonates undergoing replacement transfusion with packed
RBCs is shown in Table A-14.

##### Table A-14. Dose of DEHP received from replacement transfusion in neonates 

+---------------+-------------+---------------+----------------------+
| Blood product | Volume^1^   | Estimated     | DEHP dose^3^         |
|               |             | DEHP          |                      |
|               | \(ml\)      | con           | (mg/kg/day)          |
|               |             | centration^2^ |                      |
|               |             | (μg/ml)       |                      |
+---------------+-------------+---------------+----------------------+
|               |             |               |                      |
+---------------+-------------+---------------+----------------------+
| RBCs          | 33.6        | 123.1         | 0.3                  |
+---------------+-------------+---------------+----------------------+
|               |             |               |                      |
+---------------+-------------+---------------+----------------------+
| FFP           | 2.4         | 26.7          | 0.004                |
+---------------+-------------+---------------+----------------------+
|               |             |               |                      |
+---------------+-------------+---------------+----------------------+

^1^Mean volume infused over 14 days in one of two NICUs

^2^Upper-bound concentration as reported by Plonait et al. (1993) for
packed cells and by Shintani et al. (1985) for FFP

^3^Assumes mean body weight of 1.073 kg per Ringer et al. (1998)

The DEHP dose calculated in Table A-14 is based on an upper-bound
estimate of DEHP concentration, but a mean estimate of RBC infusion
volume. Previously, it was common practice to only use the freshest
blood from the blood bank to transfuse neonates. However, it has become
increasingly common to transfuse individual neonates repeatedly from one
unit of stored packed cells, to reduce the potential for viral
transmission. As a result, it is reasonable to use an upper-bound value
for DEHP concentration in estimating the dose of DEHP received by these
patients. An upper-bound estimate of DEHP dose would take into account
upper-bound values for DEHP concentration and the volume infused RBCs.
The upper confidence limit of the RBC infusion volume reported by Ringer
et al. (1998) for one NICU is 79.6 ml (33.6 +/- 46). Consequently, the
upper-bound dose of DEHP that could be received by a 1 kg neonate
receiving replacement transfusion over 14 days is 0.7 mg/kg/day.

Since blood used for replacement transfusions is typically drawn up from
the storage bag with a syringe and injected into the patient, there is
no need to account for DEHP released from infusion sets. However, if
blood product are administered via an infusion pump, then the amount of
DEHP received by a pediatric patient would be considerably greater. For
example, Loff et al. (2000) found that up to 8.1 mg of DEHP was released
from PVC infusion tubing following perfusion of 20 ml of fresh frozen
plasma through the tubing for 1 hour. This would result in a DEHP dose
of around 4 mg/kg/day for a 2 kg child.

*Replacement transfusion for adults undergoing surgical procedures*

Vamvakas and Carven (2000) recently quantified the number of RBC units
transfused into patients undergoing coronary artery bypass graft (CABG)
surgery as a function hospital length of stay (LOS). Data are not
provided on the concentration of DEHP in each unit of RBCs transfused;
however, an estimate of the dose of DEHP received by these patients can
be estimated from information on the number of units transfused during
their hospital stay and the mean and upper-bound values for DEHP
concentration in RBC concentrates, as reported by Plonait et al. (1993).
The mean number of units of RBCs transfused into these patients in the
Vamvakas and Carven (2000) study was 4.1 over a mean hospital LOS of 9
days. Assuming a mean DEHP concentration in the RBC concentrates of 44.8
μg/ml, the mean dose of DEHP received from transfusion in patients
undergoing CABG is:

4.1 units x 44.8 μg/ml x 350 ml/unit x 1/70 kg x 1/9 days = 0.1
mg/kg/day.

The maximum hospital LOS for patients in this study was 63 days. The
maximum number of units of RBCs received was 23. Since LOS is highly
correlated with the number of units transfused in this study, it is
likely that the patients with the longest hospital stays also received
the greatest number of RBC transfusions. As a result, an upper-bound
estimate of the dose of DEHP received by these patients from transfusion
would be:

23 units x 123.1 μg/ml x 350 mg/unit x 1/70 x 1/63 days = 0.2 mg/kg/day.

These estimates do not include any DEHP that may be released from
infusion sets or from CPB tubing.

### 

### *Long-term blood transfusion*

Patients with some chronic illnesses and those receiving antineoplastic
chemotherapy often become anemic and require blood transfusion. The dose
of DEHP received by patients undergoing long-term blood transfusion is
estimated below.

######### Leukemia and aplastic anemia

Jacobson et al. (1977) determined the DEHP dose received by patients
with leukemia and aplastic anemia receiving red cells, whole blood, and
platelets over the course of one year (Table A-15).

Table A-15. DEHP exposure over a one-year exposure period in patients
with aplastic anemia and leukemia (adapted from Jacobson et al., 1977)

  ----------- ------------ ---------- ----------- ---------- -------- --------------
              Type and                            DEHP dose           
              number of                           (Range)             
              units                                                   
              transfused                                              
              (Range)                                                 

  Diagnosis   Red cells    Whole      Platelets   Total mg   mg/kg    mg/kg/day^1^
                           blood                                      

                                                                      

  Aplastic    4 to 95      6 to 31    19 to 67    56 to 365  2.1 to   0.006 to 0.04
  anemia                                                     14.4     

  Leukemia    10 to 95     1 to 36    16 to 146   151 to     3.6 to   0.01 to 0.08
                                                  1500       27.5     
  ----------- ------------ ---------- ----------- ---------- -------- --------------

^1^When time-averaged over one year

######### Sickle cell disease

Patients with sickle cell disease are typically transfused with 1-2
units of packed cells every 2-4 weeks (McCullough, 1998). Levels of DEHP
in packed cells range from 4-123 μg/ml, as reported by Plonait et al.
(1993) and 174 μg/ml as reported by Rock et al. (1987). Using the data
from Plonait et al. (1993) as an upper-bound value for the concentration
of DEHP in packed red cells, the dose of DEHP received by a patient with
sickle cell disease would be:

123.1 μg/ml x 350 ml/unit x 2 units/14 days x 0.001 μg/mg x 1/70 kg =
0.09 mg/kg/day.

*Chemotherapy-associated anemia*

Anemia is a common problem in patients undergoing chemotherapy for
cancer treatment. As discussed by Barrett-Lee et al. (2000), 33% of
patients receiving chemotherapy will require blood transfusion during
their course of treatment. Estrin et al. (1999) reported that an average
of 5.1 red blood cell units were infused per patient undergoing
chemotherapy.

The data of Veach et al. (1998) allow estimate to be made of the number
of transfusions given in each treatment cycle of chemotherapy. For
example, Taxol is administered in a regimen that involves 3-week cycles
with 3 cycles given in a typical course of treatment. Patients receiving
Taxol in the Veach et al. (1998) study received about 3 transfusions
during the course of therapy, or about 1 transfusion (presumably packed
red cells) every 3 weeks. Therefore, the upper-bound estimate of DEHP
exposure in this scenario is:

123.1 μg/ml x 350 ml/unit x 1 unit/21 days x 0.001 μg/mg x 1/70 kg =
0.03 mg/kg/day.

*Maintenance treatment of clotting disorders*

Cryoprecipitates containing clotting factors are administered to
patients with clotting disorders. Marcel (1973) found that
cryoprecipitate packs contained from 0.8 to 1.9 mg of DEHP each. Since
patients with clotting disorders can receive up to 400 bags of
cryoprecipitate in one year, the total DEHP dose received by these
patients is on the order of 0.03 mg/kg/day.

# A.1.4 Cardiopulmonary bypass and ECMO

Cardiopulmonary bypass is used in a number of cardiac surgical
procedures (e.g., heart valve replacement, CABG surgery, heart
transplantation, correction of congenital defects) and is also used as a
means to oxygenate the blood during cardiac or pulmonary failure.
Cardiopulmonary bypass used as a means to supplement blood oxygenation
is termed extracorporeal membrane oxygenation (ECMO). Since considerable
lengths of PVC tubing is typically used in heart-lung bypass circuits
(i.e., 600 cm of PVC tubing can be used in ECMO circuits) the potential
exists for patients undergoing these procedures to be exposed to DEHP.

Barry et al. (1989) showed that levels of DEHP and MEHP increased
dramatically in patients who had undergone cardiopulmonary bypass during
cardiac surgery. Although the dose of DEHP or MEHP received by these
patients only from the CPB device and PVC tubing was not calculated, the
total dose of these phthalate esters from all sources (i.e., tubing,
transfusions) was estimated (Table A-16).

Table A-16. Dose of DEHP received during cardiac surgery (Barry et al.,
1989)

  ----------------------------------- ----------------- -----------------
  Procedure                           DEHP dose         MEHP dose
                                      (mg/kg/day)^1^    (mg/kg/day)^1^

                                                        

  Coronary artery bypass graft (CABG) 15.4 to 72.9      2.2 to 8.0

  Orthotopic heart transplantation    2.3 to 21         0.45 to 2.5

  Artificial heart transplantation    3.8 to 167.9      0.25 to 18.8

                                                        
  ----------------------------------- ----------------- -----------------

^1^in the first 24 hours following surgery

The concentration of DEHP and MEHP measured in the blood of children
undergoing cardiopulmonary bypass during corrective surgery for
congenital heart defects ranged from 1.1 to 5.06 μg/ml for DEHP at the
end of CPB and 0.06 to 2.66 μg/ml for MEHP at the end of CPB (Barry et
al., 1989).

Two groups of investigators, Shneider et al. (1989) and Karle et al
(1997), have estimated the dose of DEHP received by infants undergoing
ECMO (Table A-17).

##### Table A-17. Dose of DEHP received by infants undergoing ECMO

+-----------------------+-----------------------+-----------------------+
| **DEHP dose range**   | **DEHP concentration  | **Study**             |
|                       | in blood during ECMO  |                       |
| **(mg/kg)**           | (μg/ml)**             |                       |
+-----------------------+-----------------------+-----------------------+
|                       |                       |                       |
+-----------------------+-----------------------+-----------------------+
| 4.7 to 34.9           | 0 to 34.9^1^          | Karle et al. (1997)   |
+-----------------------+-----------------------+-----------------------+
|                       |                       |                       |
+-----------------------+-----------------------+-----------------------+
| 42 to 140^2^          | 26.8^3^               | Shneider et al.       |
|                       |                       | (1989)                |
|                       | 33.5^4^               |                       |
+-----------------------+-----------------------+-----------------------+
|                       |                       |                       |
+-----------------------+-----------------------+-----------------------+

^1^Depending on circuit, normalized to a 4 kg infant

^2^3 to 10 day course of treatment

^3^Following 14 days of ECMO

^4^Following 24 days of ECMO

Information is unavailable to accurately estimate the dose of DEHP
received by these patients on a mg/kg/day basis, since the exposure
period is represented as a range (3-10 days). However, if we assume that
the larger DEHP doses were received by patients undergoing this
procedure for 10 days, the time averaged dose of DEHP received by these
neonates is expected to be 3.5 to 14 mg/kg/day.

Estimates of DEHP dose derived by Karle et al. (1997) are based on the
rate at which DEHP is extracted from ECMO tubing by circulating blood
*in vitro*. It is interesting to note that Karle et al. (1997)
demonstrated that little or no DEHP was released from heparinized PVC
tubing. Although data are not available on the dose of DEHP received by
patients undergoing ECMO using a heparin-coated circuit, it is
anticipated, based on the results of the Karle et al. (1997) study, that
many patients currently undergoing this procedure will receive little or
no DEHP from the ECMO tubing. Although heparin-coated tubing is
available in the US, the FDA has not approved the use of heparinized
ECMO circuits.

To reduce circuit preparation time, many ECMO centers preprime the ECMO
circuits with normal saline and hold them in a preprimed state for as
long as 30 days. As might be expected, Riley et al. (1997) found no DEHP
(level of detection 120 ng/ml) in normal saline used to preprime ECMO
circuits, even after being preprimed for as long as 4 weeks.

Based on the data collected by Roy et al (2000), it is assumed that
fewer than 1000 infants undergo this procedure annually in the US.

### A.1.5 Hemodialysis and peritoneal dialysis

# A.1.5.1 Hemodialysis

Hemodialysis represents a medical procedure that has the potential to
deliver considerable doses of DEHP to a patient. For example, Faouzi et
al. (1999) recently reported that, on average, 75.2 mg of DEHP was
extracted during a single dialysis session, with a range of 44.3 to
197.1. Assuming a patient receives hemodialysis three times per week,
the time-averaged dose of DEHP received on a daily basis ranges from 19
to 84.5 mg/day. This value is consistent with that reported by other
investigators (Table A-18).

###### Table A-18. Dose of DEHP Delivered During Hemodialysis

+--------------+-------------------------------------------------------+
|              |                                                       |
+--------------+-------------------------------------------------------+
| **DEHP       | **Study**                                             |
| Dose**       |                                                       |
|              |                                                       |
| **(          |                                                       |
| mg/day)^1^** |                                                       |
+--------------+-------------------------------------------------------+
|              |                                                       |
+--------------+-------------------------------------------------------+
| 19 to 84.5   | Faouzi et al. (1999)                                  |
+--------------+-------------------------------------------------------+
| 10.2 to      | Pollack et al. (1985b)                                |
| 154.3        |                                                       |
+--------------+-------------------------------------------------------+
| 3.9 to 64.2  | Gibson et al. (1976)                                  |
+--------------+-------------------------------------------------------+
| 13.7 to 38.5 | Kevy et al (1981)                                     |
+--------------+-------------------------------------------------------+
| 19.7         | Flaminio et al. (1988)                                |
+--------------+-------------------------------------------------------+
| 6.4          | Fayz et al. (1977)                                    |
+--------------+-------------------------------------------------------+
| 4.3          | Easterling et al. (1974)                              |
+--------------+-------------------------------------------------------+

^1^Assuming hemodialysis 3 times/week

Faouzi et al. (1999) point out that not all infused DEHP is retained by
the patient. These investigators have estimated that 3.6 to 59.6 mg of
DEHP is retained in a single dialysis session. Assuming 3 dialysis
sessions per week, this dose is equivalent to a time-averaged dose of
0.02 to 0.36 mg/kg/day for a 70 kg patient.

Data are also available on the concentration of DEHP and MEHP in the
blood of patients undergoing hemodialysis (Table A-19).

**Table A-19. Concentration of DEHP and MEHP in the blood of patients
undergoing hemodialysis.**

+-----------------------+-----------------------+-----------------------+
| Study                 | DEHP Concentration    | MEHP Concentration    |
|                       |                       |                       |
|                       | (μg/ml)               | (μg/ml)               |
+-----------------------+-----------------------+-----------------------+
| Faouzi et al. (1999)  | 2 to 3 (approx.)      |                       |
+-----------------------+-----------------------+-----------------------+
| Pollack et al.        | 0.3 to 7.6            | 0.9 to 2.83           |
| (1985b)               |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Nassberger et al.     | 0.8 to 4.2            |                       |
| (1987)                |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Malik et al. (1983)   | 0.4 to 1.0            |                       |
+-----------------------+-----------------------+-----------------------+
| Lewis et al (1978)    | 0.3 to 1.9            |                       |
+-----------------------+-----------------------+-----------------------+

##### 

##### 

##### A.1.5.2 Peritoneal dialysis

Since peritoneal dialysis fluids are crystalloid in nature, it is not
surprising that little DEHP is delivered to a patient in this procedure.
Nassburger et al. (1987) measured levels of DEHP in peritoneal dialysis
solution ranging from 4 to 11 μg/L. Similarly, DEHP concentrations in
peritoneal dialysis fluid ranged from 1.1 to 3.7 μg/L, as measured by
Sugimura et al. (2001). However, Mettang et al. (1996) found DEHP levels
in dialysis fluid that ranged from 21 to 130 μg/L (Table A-20). Assuming
a patient undergoing continuous ambulatory peritoneal dialysis (CAPD) is
dialyzed with 8 L of fluid/day, the upper-bound estimate of the daily
dose of DEHP infused into the peritoneum would be on the order of 1
mg/day (0.13 μg/ml x 8,000 ml/day x 0.001 mg/μg). Since the majority of
an intraperitoneally injected dose of DEHP is not be absorbed (Rhodes et
al., 1983) the administered dose of 1 mg/day is likely to overestimate
the absorbed dose. Furthermore, a considerable amount of the infused
DEHP will be returned upon drainage of the perfusate from the
peritoneum.

It is interesting to note that both Nassburger et al. (1987) and Mettang
et al. (1996) observed that the concentration of MEHP in dialysis fluid
was considerably greater than levels of DEHP (Table A-20).

##### Table A-20. Levels of DEHP and MEHP in peritoneal dialysis solution 

+-----------------------+-----------------------+-----------------------+
| Study                 | DEHP Concentration    | MEHP Concentration    |
|                       |                       |                       |
|                       | (μg/ml)               | (μg/ml)               |
+-----------------------+-----------------------+-----------------------+
| Nassberger et al.     | 0.004 to 0.011        | 0.315 to 0.396        |
| (1987)                |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Mettang et al. (1996) | 0.021 to 0.13         | 0.137 to 0.239        |
+-----------------------+-----------------------+-----------------------+

Although it is unlikely that all of the DEHP or MEHP that is infused
into the peritoneum in CAPD patients is systemically absorbed,
Nassberger et al. (1987) and Mettang et al. (1996, 2000) measured
dramatic increases in levels of DEHP and MEHP in the serum of patients
undergoing peritoneal dialysis, therefore, some percentage of the
compound in the dialysate is undoubtedly absorbed. Unfortunately, data
(e.g. AUC data) are unavailable to estimate absorbed dose of phthalates
in patients undergoing this procedure. Phthalic acid is the major
metabolite identified in the serum of patients undergoing CAPD (Mettang
et al., 1999, 2000). The use of a plasticizer-free peritoneal dialysis
system had little effect on levels of DEHP or MEHP measured in patients
undergoing CAPD, as compared to serum levels found in patients using a
conventional peritoneal dialysis, however, serum levels of phthalic acid
were significantly lower in patients using the phthalate-free device.

Although the dose of DEHP or MEHP absorbed across the peritoneum by
patients undergoing CAPD is likely to be low, as compared to other
procedures, the endpoint of concern in patients exposed to DEHP and MEHP
from CAPD may be a "local" one - peritoneal sclerosis - an endpoint that
is not affected by the systemically absorbed dose.

**A.1.6 Apheresis**

Data are unavailable on the dose of DEHP received by donors undergoing
apheresis. However, Doull et al. (1999) used two assumptions to derive
an estimate of the DEHP dose received by individuals undergoing this
procedure: 1) that data on the amount of DEHP released during
hemodialysis provide an upper-bound estimate of DEHP dose for this
procedure and 2) that leaching of DEHP from PVC apheresis tubing is
linear over time. If 74 mg of DEHP are released during a hemodialysis
procedure lasting 5 hours (a value consistent with that reported by
Fauozi et al., 1999b), it was assumed by Doull et al. (1999) that 14.8
mg of DEHP could be released during one apheresis procedure lasting one
hour. Further assuming that platelet/plasma donation occurs once/month,
the time averaged dose of DEHP received by a donor would be around 0.5
mg/day. FDA regulations stipulate that patients cannot donate platelets
more than twice per month. Also, 2 hours is a more realistic estimate
for the duration of an apheresis procedure. Therefore, assuming the dose
of DEHP received by an apheresis donor is probably more on the order of:

74 mg/5 hours x 2 hours x 2 procedures/month x month/30 days = 1.97
mg/day.

This dose is equivalent to 0.03 mg/kg/day for a 70 kg donor; however, it
should be pointed out that there is considerable uncertainty associated
with this estimate.

**A.2 Oral Exposure**

In the medical device context, oral exposure to DEHP can occur following
release of this phthalate from enteral feeding bags and tubing or from
nasogastric tubing used for aspiration of stomach contents and
decompression of the stomach. In addition, a means of oral exposure to
DEHP that has largely been ignored is lactational transfer of DEHP to
nursing infants. As discussed below, nursing infants of women receiving
hemodialysis can theoretically receive a very large daily dose of DEHP.
An additional source of oral exposure to phthalate esters, release from
denture material, is possible. Although DEHP has been detected in
leachates from dental composites (Lee et al., 1998), phthalates other
than DEHP are typically used as plasticizers for this application.

**A.2.1 Enteral nutrition**

The enteral feeding is becoming preferred over parenteral nutrition as a
means to provide nutrition to critically ill patients (Sigurdsson,
1997). Some patients, especially those receiving care at home or in
nursing facilities, will receive nutritional support enterally (via the
gastrointestinal tract) rather than parenterally. Exposure to DEHP can
come from the PVC bag used to store the enteral nutrition solution and
the nasogastric tube, if one is used to administer the solution.

No data are available on the extent to which DEHP is released from
enteral nutrition storage bags; however, the assumption can be made that
these bags release DEHP at the same rate as bags used to store TPN
admixtures.

An estimate of the amount of DEHP released from PVC nasogastric tubes
can be derived from the data of Khaliq et al. (1992). In this study, the
rate of DEHP release from PVC tubing was quantified using different
solvents and under various extraction conditions (temperature,
duration). Extraction of a 1 cm^2^ section of tubing for one day in
various solvents resulted in DEHP release ranging from 14A-204 µg/200
ml. Since the extraction was actually conducted in 1 ml of solvent, the
release rate for a piece of tubing with a surface area of 1 cm^2^ is
around 1 µg. A 16 Fr nasogastric tube has an internal diameter of 5.3 mm
and is typically 100 cm in length. Therefore, the surface area of a
nasogastric tube exposed to enteral feeding solution would be:

SA = 2Πrh

SA= (2)(3.14)(0.265 cm)(100 cm) = 166.4 cm^2^

Assuming a release rate of around 1 µg DEHP/cm^2^/day from the tubing,
based on the data obtained by Khaliq et al. (1992), a typical adult
nasogastric tube would be expected to release DEHP at a rate of:

166.4 cm^2^ x 1 µg DEHP/cm^2^/day x 0.001 mg/μg = 0.17 mg/day

on the first day of use. After 15 days of extraction, the tubing
sections extracted by Khaliq et al. (1992) yielded 625-1008 μg of
DEHP/200 ml of solvent, equivalent to a rate of 0.2 to 0.34 μg/cm^2^/day
for a 1 cm^2^ section of tubing extracted into 1 ml. An upper-bound
estimate of the rate at which DEHP is released from a 100 cm, 16 Fr
nasogastric tube kept in place for 15 days would be:

166.4 cm^2^ x 0.34 μg/cm^2^/day x 0.001 mg/μg= 0.057 mg/day.

This value does not take into account any DEHP that is released from the
nonlumenal side of the tubing, although some release from this surface
undoubtedly occurs.

Long-term (\> 30 days) enteral nutrition is typically administered via a
gastrostomy tube. These tubes are almost always made from polyurethane
or silicone, thereby minimizing exposure to DEHP.

The total amount of DEHP received by a patient receiving enteral
nutrition can be estimated from is the sum of the amount released from
the bag and from the tubing. Using the data from Mazur et al. (1989),
and assuming that that the enteral nutrition admixture contains a
similar amount of lipid as the parenteral admixture, an upper-bound
estimate of this dose is:

9.3 mg/day (bag) + 0.17 mg/day tubing = 9.47 mg/day.

A more typical daily dose from enteral nutrition would probably be on
the order of:

3 mg/day (bag) + 0.057 mg/day (tubing) = 3.057 mg/day.

If the data of Allwood (1986) are used, the total dose of DEHP would be:

100 mg/day (bag) + 0.17 mg/day (tubing) = 100.17 mg/day.

By comparison, estimates of the amount of DEHP received by the general
population via food range from around 0.3 mg/day for typical individuals
to around 2 mg/day for highly exposed individuals.

**A.2.2 DEHP exposure to breastfeeding infants of nursing mothers
receiving hemodialysis**

One means of exposure to DEHP and MEHP that seems to have been largely
overlooked is lactational transfer from a nursing mother to her
offspring. The rodent studies that demonstrate adverse effects in
offspring following ingestion of milk from DEHP-exposed dams (e.g.,
Parmar et al, 1985; Dabholkar, 1988; Cimini et al., 1994; Stefanini et
al., 1997) suggest that transfer of enough DEHP or MEHP can take place
to cause adverse effects.

Levels of DEHP in human milk have been reported in two German studies.
Gruber et al. (1998) reported DEHP concentrations of 71-160 μg/kg milk
from 5 subjects (mean 93.2 +/- 37.5, median 76). In a comprehensive
review of DEHP exposures, Pfordt and Bruns-Weller (1999) reported DEHP
levels in human milk of 0-110 μg/kg milk from 5 subjects (mean 0.034 +/-
0.043, median 0.02). Presumably, none of the subjects included in each
of these studies had recently undergone medical procedures that would
have exposed them to relatively large doses of DEHP. Unfortunately,
experimental data are unavailable on levels of DEHP in milk from mothers
who have undergone or are undergoing medical procedures such as
hemodialysis. In the absence of data from these patients, it's possible
to derive preliminary estimates the concentration of DEHP and MEHP in
human milk either from the experimentally derived milk:plasma partition
coefficients for rats reported by Dostal et al. (1987) or by using
theoretical partitioning models, such as those developed by Begg and
Atkinson (1993). Dostal and colleagues (1987) report that the
milk:plasma partition coefficient for DEHP is \< 200, which is not
surprising given the lipophilic nature of this compound. Conversely, the
milk:plasma partition coefficient for MEHP is 0.33, largely because of
it's acidic nature and because it is highly bound to plasma proteins
(F~u~ about 1-2%). Use of the Phase Distribution Model of Begg and
Atkinson (1993) results in an estimated milk:plasma partition
coefficient for MEHP in humans of 0.26, a value that closely corresponds
to the experimentally derived value reported by Dostal et al. (1987).

To estimate the dose of DEHP or MEHP received by a nursing infant, data
are needed on the concentration of these phthalate esters in maternal
plasma, the milk:plasma partition coefficient (which is estimated above)
and an estimate of daily milk consumption by infants. A value of 150
ml/kg/day is typically used in risk assessments involving lactational
transfer.

Although the incidence of pregnancy in women on hemodialysis is low
(about 1-7%), these patients do give birth and some presumably some
would breastfeed their children. Levels of DEHP in these patients range
from about 0.4 to 8 μg/ml, however, the latest data from Faouzi et al.
(1999) suggests that levels of about 3 μg/ml are reached after 4 hours
of dialysis. Levels of MEHP in these patients range from 0.885 to 2.83
μg/ml, according to Pollack et al. (1985). Therefore, the dose of DEHP
received by a nursing infant from a mother on hemodialysis could be on
the order of:

3 μg/ml x 200 x 150 ml/kg/day = 90 mg/kg/day

The dose of MEHP is estimated to be approximately:

1 μg/ml x 0.33 x 150 ml/kg/day = 0.05 mg/kg/day

The actual dose of DEHP received by infants could be higher, since
Dostal et al. (1987) noted that the milk:plasma partition coefficient
for DEHP in rats was \> 200, and since upper bound values of DEHP in the
plasma of hemodialysis patients were not used. However, the actual dose
of DEHP received by these infants could be lower as well. Based on the
concentration of DEHP in human milk (around 0.1 μg/ml) and the
concentration of DEHP in plasma (also around 0.1 μg/ml), the milk:plasma
partition coefficient in humans in the general population exposed to low
doses of DEHP is probably around 1. Consequently, dose of DEHP received
by nursing infants of mothers exposed to DEHP via hemodialysis could be
much less than the 90 mg/kg/day estimate that is based on rodent data.
Because of the level of uncertainty in these estimates, TI/Dose ratios
will not be derived for this means of exposure to DEHP. Furthermore, due
to infertility in women on hemodialysis, the number of infants exposed
to these very high levels of DEHP via nursing is likely to be very small
(perhaps on the order of 100).

**A.3 Inhalation Exposure**

Since PVC tubing is used in respirators, it is theoretically possible
for some amount of this plasticizer to be released from the tubing into
the respiratory air stream and administered to the patient. Based on
levels of DEHP measured in the condensate collected from the water traps
of respirators, Roth et al (1988) estimated that a patient could receive
an inhalation dose of DEHP ranging from 1 to 4200 μg/hour. Although
patients are probably exposed to some DEHP via this method since the
water vapor in the air circulating in the PVC tubing may solubilize some
of the DEHP on the surface of the tubing, use of data on the
concentration of DEHP in the water from the respirator water trap does
not provide an accurate means to estimate DEHP dose, since this fluid is
not transferred to the patient.

A worst case scenario would involve breathing air saturated with DEHP
continuously for 24 hours/day. The vapor saturation concentration of
DEHP in air at 25°C is 5.3 μg/m^3^.

Oie et al. (1997) found that DEHP is associated with the particulate
phase as well as the vapor phase, and up to 3 times more DEHP may be
associated with the vapor phase. Consequently, the worst case
concentration of DEHP in the air would be 5.3 μg/m^3^ + 15.9 μg/m^3^ =
21.2 μg/m^3^. The default inhalation rate for an adult is 20 m^3^/day
and 9.3 m^3^/day for an 8 kg child. Therefore, the upper-bound estimate
of the dose of DEHP received by a patient via inhalation would be:

21.2 μg/m^3^ x 20 m^3^/day/70 kg x 0.001 μg/mg = 0.006 mg/kg/day (adult)

21.2 μg/m^3^ x 9.3 m^3^/day/8 kg x 0.001 μg/mg = 0.02 mg/kg/day (child)

Based on the concentration of DEHP measured in the air stream passed
through PVC respiratory tubing, Hill (1997) it is estimated that a
patient undergoing respiratory therapy would receive a daily DEHP dose
ranging from 28.4 to 94.6 μg, which is equivalent to a dose of 0.0004 to
0.001 mg/kg/day for a 70 kg adult.

Because of the uncertainties associated with this estimate, a TI value
for inhalation exposure to DEHP will not be derived.

######## 

######## *Partitioning of DEHP from an Endotracheal Tube into Respiratory Mucus*

Instead of being volatilized and delivered to the patient via the
respiratory air stream, DEHP could partition from a PVC endotracheal
tube into the respiratory tract mucus, where it could subsequently be
taken up by a patient. Latini and Avery (1999) observed stiffening and
color changes in PVC endotracheal tubes used for only a few hours and
thought that these changes may be due to a release of the plasticizer
from the material. Overnight extraction in chloroform:methanol solution
produced a loss of DEHP from the tubing ranging from 0.06-0.12 mg per mg
of tubing (Latini, 2000), equivalent to a loss of 120 mg of DEHP from a
typical pediatric endotracheal tube (Hinberg, 2000). However, the dose
of DEHP received by intubated patients from an endotracheal tube cannot
be estimated with certainty from these data for two reasons: 1) the
extraction conditions used by Latini and Avery (1999) do not necessarily
mimic the extraction conditions present *in vivo* and 2) if DEHP does
partition to respiratory mucus, a great deal of this mucus is suctioned
from intubated patients, therefore, not all of the DEHP-containing mucus
will be absorbed.

Alternately, if we assume that an endotracheal tube will release DEHP at
approximately the same rate as a nasogastric tube, then the data from
Khaliq et al. (1992) can be used to derive a rough of the amount of DEHP
released from an ET tube. Presumably, DEHP will be released from the
outside and the lumenal side of the tube. A typical pediatric ET tube
has an ID of 7.5 mm and an OD of 10 mm and a length of 32 cm, therefore,
the inner and outer surface areas of the tube are approximately 75 and
100 cm^2^, respectively. Only about one-half of the outer surface of the
tube will be in contact with the tracheal mucosa and perhaps only
one-half of the DEHP released from the lumenal side will be absorbed,
because of suctioning. Therefore, the total dose of DEHP released by the
tube is approximately:

175 cm^2^/2 x 0.34 μg/cm^2^/day = 0.03 mg/day.

**A.4 Dermal/Mucosal Exposure**

The potential exists for DEHP to be released from skin surface- or
mucosal membrane-contacting PVC devices such as urinary catheters, drug
delivery patches, occlusive dressings, oxygen masks, and endotracheal
tubes. However, there are insufficient data to accurately characterize
the amount of DEHP that would be released from these devices and taken
up by the body. Although nasogastric tubes contact the esophageal
mucosa, it is assumed that the majority of the DEHP released from these
devices is extracted from the lumenal side of the tubing and is
subsequently absorbed in the gastrointestinal tract.

Patients are assumed to have only incidental contact with PVC gloves
worn by health care workers. Since this risk assessment deals only with
potential health risks to patients, the potential risk to health care
workers from dermal exposure to DEHP will not be assessed. However, it
is useful to note that KEMI (1999) has estimated that a health care
worker wearing gloves for 2 hours/day will receive a DEHP dose of 0.007
mg/kg/day.

**A.5 Aggregate Exposure to DEHP from Multiple Medical Devices**

**A.5.1 Neonates in NICU setting**

Patients in various clinical scenarios are often exposed to multiple PVC
devices. For example, neonates in the NICU environment are exposed to
DEHP from multiple devices. Based on the dose of DEHP received in such
procedures as intravenous administration of sedatives, administration of
TPN and replacement transfusion, all common procedures in the NICU, it
is possible to estimate that a 4 kg infant could receive a DEHP dose on
the order of 3 mg/kg/day for a periods of weeks or months (Table A-21)

**Table A-21 Aggregate exposure of neonates to DEHP in the NICU
environment.**

  ----------------------------------- -----------------------------------
  Procedure                           DEHP dose (mg/kg/day)^1^

  IV administration of sedative       0.03

  IV administration of TPN            2.5

  Replacement transfusion             0.3

  Total^2^                            2.83
  ----------------------------------- -----------------------------------

^1^4 kg infant

^2^Doesn't include DEHP does from endotracheal intubation, nasogastric
tube or ECMO

# A.5.2 Adult patients undergoing ECMO

The total dose of DEHP received by patients undergoing ECMO can be
grossly underestimated if this dose is estimated simply from data on the
extent to which DEHP is released from PVC tubing used in the device.
Since these patients are multiply transfused and can receive over 600
transfused units (RBCs, platelet concentrates, FFP, cryoprecipitate)
during their course of ECMO and hospitalization, a considerable amount
of DEHP can also be received from transfused blood products as well as
the PVC used in the ECMO device. Patients undergoing ECMO are also
multiply transfused and may receive drugs (e.g., antibiotics, vitamins)
solubilized in pharmaceutical surfactants that promote DEHP release from
PVC bags. For example, an adult undergoing ECMO could receive a DEHP
dose on the order of 4 mg/kg/day, if aggregate exposure from multiple
devices is considered. The principle contribution to the total dose of
DEHP received by these patients comes from the multiple transfusions
needed by these patients, not the PVC tubing used in the ECMO device.

**A.5.3 Adult patients undergoing surgical procedures**

Adult patients receiving a coronary artery bypass graft surgery are can
receive DEHP from a during a number of medical devices, including an
endotracheal tube, IV bags and tubing (especially if a multivitamin
solution is infused), chest tubes, hemodynamic monitoring catheters,
nasal cannula, nasogastric tube, and blood bags and administration sets.
The dose of DEHP received by these patients, as estimated by Barry et
al. (1988), is based on the concentration of DEHP in the blood, and
therefore, takes into account aggregate exposure.

# A.6 Coexposure to Other Phthalate Esters

In addition to DEHP and MEHP, patients may also be exposed to other
phthalate esters used as plasticizers for medical grade PVC. Although
DEHP is by far the most commonly used plasticizer PVC, dibutyl phthalate
(DBP), diethyl phthalate (DEP), dimethyl phthalate (DMP), diisobutyl
phthalate (DIP), and butyl A-ethylhexyl phthalate (BEP) have also been
identified in extracts from PVC medical devices. For example, Khaliq et
al. (1992) quantified levels of DEHP, DBP and DMP released from PVC
nasogastric tubing. DBP and DEP have been identified as components of
PVC used for devices such as microfilters, butterfly catheters, infusion
tubing, infusion bags, and intestinal tubing at levels ranging from ≥ 1%
to \< 20% of the total volatiles extracted from the device (Wahl et al.,
1999). Other phthalates, such as DIP and BEP were also identified by
Wahl et al. (1999) as constituting a fraction of the volatiles extracted
from some devices (Table A-22).

**Table A-22. Phthalate esters identified in extracts from various
medical devices (adapted from Wahl et al., 1999)**

+--------------------+---------+---------+---------+---------+---------+
| **Device**         | **DEP** | *       | **DBP** | **BEP** | *       |
|                    |         | *DIBP** |         |         | *DEHP** |
+--------------------+---------+---------+---------+---------+---------+
| # Syringe 60 ml    | ## A    |         | A       |         | A       |
+--------------------+---------+---------+---------+---------+---------+
| Insulin syringe    | A       |         | A       |         |         |
+--------------------+---------+---------+---------+---------+---------+
| Heparin syringe    | A       |         | A       |         | B       |
+--------------------+---------+---------+---------+---------+---------+
| Microfilter 40 μl  | B       |         | B       | A       | B       |
+--------------------+---------+---------+---------+---------+---------+
| ## Serum monovette | A       |         | A       |         |         |
+--------------------+---------+---------+---------+---------+---------+
| Butterfly          | B       |         |         | B       | B       |
+--------------------+---------+---------+---------+---------+---------+
| Luerlock obturator | A       |         | A       |         | B       |
+--------------------+---------+---------+---------+---------+---------+
| Infusion tubing    | # A     |         | B       | B       | C^3^    |
+--------------------+---------+---------+---------+---------+---------+
| Infusion bag       | A       |         | B       | A       | C       |
+--------------------+---------+---------+---------+---------+---------+
| Blood storage bag  |         |         |         |         | C       |
+--------------------+---------+---------+---------+---------+---------+
| Blood infusion     | A       | B       | A       | B       | C       |
| tubing             |         |         |         |         |         |
+--------------------+---------+---------+---------+---------+---------+
| Intestinal tubing  | B       |         | B       |         | B       |
+--------------------+---------+---------+---------+---------+---------+
| Dialysis tubing    | A       |         | A       |         | C       |
+--------------------+---------+---------+---------+---------+---------+

A \<1% total volatiles; B \< 20% total volatiles; C \< 85% total
volatiles

While the data of Wahl et al. (1999) do not enable a quantitative
estimate of the dose of each of these phthalate ester to be derived,
they do indicate that patient exposure to multiple phthalate esters is
possible following the use of PVC medical devices.

Patient exposure to multiple phthalates is also evidenced by data
reported by Ching et al. (1981). It is interesting to note that levels
of DBP in the serum of surgical patients exceeded that of DEHP in many
cases (Table A-23).

Table A-23. Serum plasticizers levels measured in surgical patients
(Ching et al., 1981)

+-----------------------+-----------------------+-----------------------+
| ## **Patient**        | **DBP (μg/ml)**       | **DEHP (μg/ml)**      |
+-----------------------+-----------------------+-----------------------+
|                       |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Control               | 37                    | 3                     |
+-----------------------+-----------------------+-----------------------+
| 1                     | 35                    | 8                     |
+-----------------------+-----------------------+-----------------------+
| 2                     | 0.2                   | 4                     |
+-----------------------+-----------------------+-----------------------+
| 3                     | 41                    | 14                    |
+-----------------------+-----------------------+-----------------------+
| 4                     | 0.3                   | 7                     |
+-----------------------+-----------------------+-----------------------+
| 5                     | 0                     | 6                     |
+-----------------------+-----------------------+-----------------------+

It's not clear, however, that exposure to DBP occurred following patient
exposure to PVC devices, since levels of this compound were higher than
those of DEHP in the single control patient enrolled in the study. Ching
et al. (1981) speculate that the measured DBP may have come from alcohol
wipes used in the blood collection process.

In addition, the general population is exposed to multiple phthalates
(Blount et al., 2000), in particular, DBP, DEP and BBP. Presumably,
patients can be exposed to these phthalates esters from environmental
sources and to DEHP from medical devices. Since phthalate esters can
produce similar adverse effects in exposed experimental animals, it may
be reasonable to develop an approach to account for co-exposure to these
compounds. If DBP, DEHP and other phthalate esters that patients are
exposed to exert their effects via a common toxicological mechanism of
action, it may be prudent to develop such an approach for phthalate
esters. This approach is discussed in greater detail in Section 4.0,
Risk Characterization.

# A.7 Conclusions

Patients undergoing procedures such as IV therapy and IV administration
of drugs, transfusion of blood products, hemodialysis, peritoneal
dialysis, artificial ventilation, enteral and parenteral nutrition
support, cardiopulmonary bypass and ECMO can be exposed to DEHP released
from PVC medical devices. The estimated dose of DEHP received by adult
and neonatal patients undergoing various medical procedures is
summarized in Table A-24. These values will be used to derive TI/Dose
ratios in Section 4.0.

**Table A-24. Estimated dose of DEHP received by adult and neonatal
patients undergoing various medical procedures.**

+----------------------------------------+---------------+------------+
| Procedure                              | DEHP dose     |            |
|                                        |               |            |
|                                        | (mg/kg/day)   |            |
+----------------------------------------+---------------+------------+
|                                        | Adult (70 kg) | Neonate (4 |
|                                        |               | kg)        |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| **Infusion of crystalloid IV           | 0.005         | 0.05       |
| solutions**                            |               |            |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| **IV infusion of drugs requiring       |               |            |
| pharmaceutical vehicles for            |               |            |
| solubilization**                       |               |            |
+----------------------------------------+---------------+------------+
| When administered according to         | 0.05          | 0.03       |
| manufacturer's instructions            |               |            |
+----------------------------------------+---------------+------------+
| When stored mixed and stored at room   | 0.74          |            |
| temperature for 48 hr                  |               |            |
+----------------------------------------+---------------+------------+
| ########                               |               |            |
+----------------------------------------+---------------+------------+
| ######## TPN administration            |               |            |
+----------------------------------------+---------------+------------+
| Without added lipid                    | 0.03          | 0.03       |
+----------------------------------------+---------------+------------+
| With added lipid                       | 0.18          | 2.5        |
+----------------------------------------+---------------+------------+
| Lipid alone                            | 0.04          |            |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| ######## Blood transfusion             |               |            |
+----------------------------------------+---------------+------------+
| Trauma patient                         | 8.5           |            |
+----------------------------------------+---------------+------------+
| Transfusion/ECMO in adult patient      | 3.0           |            |
+----------------------------------------+---------------+------------+
| Exchange transfusion/neonate           |               | 22.6       |
+----------------------------------------+---------------+------------+
| Replacement transfusion/neonate in     |               | 0.65       |
| NICU                                   |               |            |
+----------------------------------------+---------------+------------+
| Replacement transfusion/correction of  | 0.12          |            |
| anemia in                              |               |            |
|                                        |               |            |
| patients receiving chemotherapy and in |               |            |
| patients                               |               |            |
|                                        |               |            |
| with sickle cell disease               |               |            |
+----------------------------------------+---------------+------------+
| Replacement transfusion/surgical       | 0.28          |            |
| patient                                |               |            |
|                                        |               |            |
| undergoing CABG                        |               |            |
+----------------------------------------+---------------+------------+
| Treatment of clotting disorders with   | 0.03          |            |
| cryoprecipitate                        |               |            |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| ######## Cardiopulmonary bypass        |               |            |
+----------------------------------------+---------------+------------+
| CABG                                   | 1             |            |
+----------------------------------------+---------------+------------+
| Orthotopic heart transplant            | 0.3           |            |
+----------------------------------------+---------------+------------+
| Artificial heart transplant            | 2.4           |            |
+----------------------------------------+---------------+------------+
| ########                               |               |            |
+----------------------------------------+---------------+------------+
| ######## ECMO                          |               | 14         |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| ######## Apheresis                     | 0.03          |            |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| **Hemodialysis**                       | 0.36          |            |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| **Peritoneal dialysis**                | \< 0.01       |            |
+----------------------------------------+---------------+------------+
|                                        |               |            |
+----------------------------------------+---------------+------------+
| **Enteral nutrition**                  | 0.14          | 0.14       |
+----------------------------------------+---------------+------------+

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**Annex B: Summary of Results of Parenteral Toxicity Studies of DEHP**

# Hepatic effects observed following parenteral administration of DEHP to experimental animals

+-----------+------------+---+---------+------+------+---------------+
| Study     | Species    | R | Fre     | N    | L    | Effect        |
|           |            | o | quency/ | OAEL | OAEL |               |
|           |            | u |         |      |      |               |
|           |            | t | D       | (mg  | (mg  |               |
|           |            | e | uration | /kg/ | /kg/ |               |
|           |            |   |         | day) | day) |               |
+-----------+------------+---+---------+------+------+---------------+
| Pollack   | Rat        | I | Daily   |      | 3906 | Hepatomegaly  |
| et al.    |            | P | for 7   |      |      |               |
| (1989)    |            |   | days    |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| S         | Rat        | I | 21 days |      | 714  | Altered liver |
| rivastava |            | P |         |      |      | enzymes       |
| et al.    |            |   |         |      |      |               |
| (1975)    |            |   |         |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Seth et   | Rat        | I | 10 days |      | 976  | Mild hepatic  |
| al.       |            | P |         |      |      | congestion    |
| (1979)    |            |   |         |      |      | and bile duct |
|           |            |   |         |      |      | proliferation |
+-----------+------------+---+---------+------+------+---------------+
| Nair et   | Rat        | I | Up to   | 3.8  |      | No adverse    |
| al.       |            | P | 7.5     |      |      | effect, but   |
| (1998)    |            |   | mg/kg   |      |      | decreased     |
|           |            |   | as a    |      |      | level of      |
|           |            |   | single  |      |      | Vitamin E in  |
|           |            |   | adminis |      |      | the liver at  |
|           |            |   | tration |      |      | doses ≥ 0.75  |
|           |            |   | or      |      |      | mg/kg/day     |
|           |            |   | every   |      |      |               |
|           |            |   | other   |      |      |               |
|           |            |   | day for |      |      |               |
|           |            |   | 12 days |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Leber et  | Rat        | I | Single  | 2000 |      | No adverse    |
| al.       |            | P | adminis |      |      | effect        |
| (1979)    |            |   | tration |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Leber et  | Rat        | I | 2000    |      | 1000 | Hepatomegaly, |
| al.       |            | P | mg/kg   |      |      | ↑ MFO         |
| (1979)    |            |   | every   |      |      | activity, ↓   |
|           |            |   | other   |      |      | GST activity  |
|           |            |   | day for |      |      |               |
|           |            |   | 14 days |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Leber et  | Rat        | I | 56 x    |      | 2    | Hepatomegaly, |
| al.       |            | P | 500     |      | 10.5 | ↑ MFO         |
| (1979)    |            |   | mg/kg   |      |      | activity, ↓   |
|           |            |   | over 19 |      |      | GST activity  |
|           |            |   | weeks   |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Rathinam  | Rat        | I | Once    |      | 1000 | ↓ Liver       |
| et al.    |            | P | daily   |      |      | weight, ↓ MFO |
| (1990)    |            |   | for 7   |      |      | activity, ↑   |
|           |            |   | days    |      |      | GST activity  |
+-----------+------------+---+---------+------+------+---------------+
| K         | Hamster    | I | 30      |      | 4.3  | Morphological |
| omitowski |            | P | mg/kg   |      |      | changes to    |
| et al.    |            |   | once    |      |      | hepatocytes   |
| (1986)    |            |   | with    |      |      | using image   |
|           |            |   | sa      |      |      | analysis, no  |
|           |            |   | crifice |      |      | effects seen  |
|           |            |   | after 7 |      |      | histop        |
|           |            |   | days    |      |      | athologically |
+-----------+------------+---+---------+------+------+---------------+
| Schultz   | Mouse      | I | 6 weeks |      | 250  | Hepatomegaly  |
| et al.    |            | P |         |      |      |               |
| (1975)    |            |   |         |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Calley et | Mouse      | I | Daily   |      | 250  | Hepatomegaly  |
| al.       |            | P | for 6   |      |      |               |
| (1966)    |            |   | weeks   |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Rhodes et | Marmoset   | I | Once    |      | 1000 | No increased  |
| al.       |            | P | daily   |      |      | liver weight  |
| (1986)    |            |   | for 14  |      |      |               |
|           |            |   | days    |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Lawerence | Rat        | S | 1x/week |      | 714  | No effect on  |
| (unp      |            | C | for 12  |      |      | liver weight  |
| ublished) |            |   | weeks   |      |      | or BSP        |
|           |            |   |         |      |      | clearance     |
+-----------+------------+---+---------+------+------+---------------+
| Greener   | Rat        | I | 18 days | 91.7 | 1    | Hepatomegaly, |
| et al.    |            | V |         |      | 64.8 | ↑SGOT         |
| (1987)    |            |   |         |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Sjoberg   | Rat        | I | 50 or   | 25   | 250  | Increased     |
| et al.    |            | V | 500     |      |      | liver weight, |
| (1985a)   |            |   | mg/kg   |      |      | no change in  |
|           |            |   | every   |      |      | liver enzymes |
|           |            |   | other   |      |      | or BSP        |
|           |            |   | day for |      |      | clearance     |
|           |            |   | 12 days |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Baxter    | Rat        | I | 18 days | 62   |      | No adverse    |
| (2000)    |            | V | post    |      |      | effects       |
|           |            |   | natally |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Baxter    | Rabbit     | I | 28 days | 62   |      | No adverse    |
| (2000)    |            | V | post    |      |      | effects       |
|           |            |   | natally |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| AdvaMed   | Rat        | I | 21 days | 60   | 300  | Hepatomegaly  |
| (2001)    |            | V |         |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Garvin et | Rat        | I | 2x/week |      |      | No            |
| al.       |            | V | for 26  |      |      | significant   |
| (1976)    |            |   | or 63   |      |      | difference in |
|           |            |   | days    |      |      | total         |
|           |            |   |         |      |      | billirubin,   |
|           |            |   |         |      |      | SGOT levels   |
|           |            |   |         |      |      | or BSP        |
|           |            |   |         |      |      | clearance     |
+-----------+------------+---+---------+------+------+---------------+
| Rutter    | Dog        | I | Daily   |      | 21.4 | Hepatomegaly, |
| (1973)    |            | V | in      |      |      | altered liver |
|           |            |   | jection |      |      | enzymes       |
|           |            |   | for 21  |      |      |               |
|           |            |   | cons    |      |      |               |
|           |            |   | ecutive |      |      |               |
|           |            |   | days    |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Rutter    | Dog        | I | 6       | 1    |      | No adverse    |
| (1975)    |            | V | d       |      |      | effects       |
|           |            |   | ay/week |      |      |               |
|           |            |   | for 4   |      |      |               |
|           |            |   | weeks   |      |      |               |
+-----------+------------+---+---------+------+------+---------------+
| Jacobson  | Rhesus     | I | 1 year  |      | 0    | Hist          |
| et al.    | monkey     | V |         |      | .021 | opathological |
| (1977)    |            |   |         |      |      | changes in    |
|           |            |   |         |      |      | the liver,    |
|           |            |   |         |      |      | decreased BSP |
|           |            |   |         |      |      | clearance     |
+-----------+------------+---+---------+------+------+---------------+

**Pulmonary effects observed following parenteral administration of DEHP
to experimental animals**

+----------+----+-----+-------+-------+-------+---------------------+
| *        | *  | **  | **Fr  | **NO  | **LO  | **Effect**          |
| *Study** | *S | Veh | equen | AEL** | AEL** |                     |
|          | pe | icl | cy/** |       |       |                     |
|          | ci | e** |       | **(mg | **(mg |                     |
|          | es |     | **    | /kg/d | /kg/d |                     |
|          | ** |     | Durat | ay)** | ay)** |                     |
|          |    |     | ion** |       |       |                     |
+----------+----+-----+-------+-------+-------+---------------------+
| Schulz   | R  | Twe | S     |       | 50    | Histopathological   |
| et al.   | at | en- | ingle |       |       | changes in lung     |
| (1975)   |    |     | dose  |       |       | without respiratory |
|          |    | D   |       |       |       | distress            |
|          |    | MSO |       |       |       |                     |
+----------+----+-----+-------+-------+-------+---------------------+
| Schulz   | R  | Twe | S     |       | 250   | Respiratory         |
| et al.   | at | en- | ingle |       |       | distress, increased |
| (1975)   |    |     | dose  |       |       | lung weight, signs  |
|          |    | D   |       |       |       | of hemorrhagic      |
|          |    | MSO |       |       |       | congestion          |
|          |    | or  |       |       |       |                     |
|          |    | Tw  |       |       |       |                     |
|          |    | een |       |       |       |                     |
+----------+----+-----+-------+-------+-------+---------------------+
| Rubin    | R  | Pla | S     |       | 200   | Dose-related        |
| and      | at | sma | ingle |       | (     | increase in lung    |
| Chang    |    |     | dose  |       | LD50) | edema and lethality |
| (1978)   |    |     |       |       |       | during exchange     |
|          |    |     |       |       |       | transfusion         |
+----------+----+-----+-------+-------+-------+---------------------+
| Rubin    | R  | Pla | S     |       | 7.7   | Increased lethality |
| and      | at | sma | ingle |       | to 13 | and presence of     |
| Chang    |    |     | dose  |       |       | hemorrhagic lungs   |
| (1978)   |    |     |       |       |       | following           |
|          |    |     |       |       |       | replacement         |
|          |    |     |       |       |       | transfusion         |
+----------+----+-----+-------+-------+-------+---------------------+
| Garvin   | R  | DEH | Twice | 1.05  |       | No pulmonary        |
| et al.   | at | P-c | a     |       |       | effects             |
| (1976)   |    | ont | week  |       |       |                     |
|          |    | ain | for   |       |       |                     |
|          |    | ing | 63    |       |       |                     |
|          |    | pla | days  |       |       |                     |
|          |    | sma |       |       |       |                     |
|          |    | e   |       |       |       |                     |
|          |    | xtr |       |       |       |                     |
|          |    | act |       |       |       |                     |
+----------+----+-----+-------+-------+-------+---------------------+
| Greener  | R  | 4%  | Daily | 164.8 |       | No pulmonary        |
| et al.   | at | BSA | for   |       |       | effects             |
| (1987)   |    |     | 18    |       |       |                     |
|          |    |     | days  |       |       |                     |
+----------+----+-----+-------+-------+-------+---------------------+
| Petersen | D  | N   | Once  | 10    |       | No gross postmortem |
| (1975)   | og | eat | daily |       |       | findings, no        |
|          |    |     | for   |       |       | abnormal clinical   |
|          |    |     | up to |       |       | signs               |
|          |    |     | 22    |       |       |                     |
|          |    |     | days  |       |       |                     |
+----------+----+-----+-------+-------+-------+---------------------+
| Rutter   | D  | N   | S     | 100   | 300   | Increased           |
| (1973)   | og | eat | ingle |       |       | respiratory rate    |
|          |    |     | dose  |       |       |                     |
+----------+----+-----+-------+-------+-------+---------------------+
| Rutter   | D  | N   | Once  |       | 50    | Red/dark blue areas |
| (1973)   | og | eat | daily |       |       | over lung surface   |
|          |    |     | for   |       |       |                     |
|          |    |     | 14    |       |       |                     |
|          |    |     | days  |       |       |                     |
+----------+----+-----+-------+-------+-------+---------------------+
| Rutter   | D  | N   | Once  |       | 21.4  | Increased relative  |
| (1973)   | og | eat | daily |       |       | lung weight,        |
|          |    |     | for 4 |       |       | histopathological   |
|          |    |     | weeks |       |       | changes             |
+----------+----+-----+-------+-------+-------+---------------------+
| Rutter   | D  | N   | Once  | 1.4   |       | No pulmonary        |
| (1975)   | og | eat | daily |       |       | effects             |
|          |    |     | for   |       |       |                     |
|          |    |     | 21    |       |       |                     |
|          |    |     | days  |       |       |                     |
+----------+----+-----+-------+-------+-------+---------------------+

#### Testicular effects observed following parenteral administration of DEHP to experimental animals 

+-----+----+-----+----+------------------+----------+--------------+
| **  | *  | **N | *  | **Effect**       | **Du     | **Study**    |
| Spe | *R | OAE | *L |                  | ration** |              |
| cie | ou | L** | OA |                  |          |              |
| s** | te |     | EL |                  |          |              |
|     | ** |     | ** |                  |          |              |
+-----+----+-----+----+------------------+----------+--------------+
| Mo  | IP |     | 2  | Testicular       | 6 weeks  | Calley et    |
| use |    |     | 50 | atrophy          |          | al. (1966)   |
+-----+----+-----+----+------------------+----------+--------------+
| Rat | IP |     | 7  | Focal            | 22 days  | Seth et al.  |
|     |    |     | 00 | degeneration of  |          | (1976)       |
|     |    |     |    | seminiferous     |          |              |
|     |    |     |    | tubules, edema   |          |              |
|     |    |     |    | of testicular    |          |              |
|     |    |     |    | interstitium     |          |              |
+-----+----+-----+----+------------------+----------+--------------+
| Mo  | IP | 100 |    | No adverse       | 5 days   | Curto and    |
| use |    |     |    | effects          |          | Thomas       |
|     |    |     |    |                  |          | (1982)       |
+-----+----+-----+----+------------------+----------+--------------+
| Mo  | IP | 50  |    | No adverse       | 20 days  | Curto and    |
| use |    |     |    | effects          |          | Thomas       |
|     |    |     |    |                  |          | (1982)       |
+-----+----+-----+----+------------------+----------+--------------+
| Rat | IP |     | 50 | ↓ testicular Zn  | 20 days  | Curto and    |
|     |    |     |    |                  |          | Thomas       |
|     |    |     |    |                  |          | (1982)       |
+-----+----+-----+----+------------------+----------+--------------+
| Rat | IP |     | 2  | ↓ testicular     | 21 days  | Agarwal et   |
|     |    |     | 82 | ATPase,          |          | al. (1989)   |
|     |    |     |    |                  |          |              |
|     |    |     |    | (higher doses)   |          |              |
|     |    |     |    | Testicular       |          |              |
|     |    |     |    | atrophy,         |          |              |
|     |    |     |    | oligospermia,    |          |              |
|     |    |     |    | seminiferous     |          |              |
|     |    |     |    | tubule           |          |              |
|     |    |     |    | degeneration,    |          |              |
+-----+----+-----+----+------------------+----------+--------------+
| Mo  | IP | 3   | 60 | ↓ sperm count,   | 5 days   | Douglas et   |
| use |    | 000 | 00 | testicular       | adminis  | al. (1986)   |
|     |    |     |    | atrophy          | tration, |              |
|     |    |     |    |                  | 12 weeks |              |
|     |    |     |    |                  | obs      |              |
|     |    |     |    |                  | ervation |              |
+-----+----+-----+----+------------------+----------+--------------+
| Rat | IP | 5   |    | No adverse       | 5 days   | Douglas et   |
|     |    | 200 |    | effects          | adminis  | al. (1986)   |
|     |    |     |    |                  | tration, |              |
|     |    |     |    |                  | 12 weeks |              |
|     |    |     |    |                  | obs      |              |
|     |    |     |    |                  | ervation |              |
+-----+----+-----+----+------------------+----------+--------------+
| Mo  | IP |     | 2  | Testicular       | 6 weeks  | Schultz et   |
| use |    |     | 50 | atrophy          |          | al. (1975)   |
+-----+----+-----+----+------------------+----------+--------------+
| Rat | IP | 3.5 |    | No adverse       | Single   | Nair et al.  |
|     |    |     |    | effects          | i        | (1998)       |
|     |    |     |    |                  | njection |              |
|     |    |     |    |                  | or every |              |
|     |    |     |    |                  | other    |              |
|     |    |     |    |                  | day for  |              |
|     |    |     |    |                  | 12 days  |              |
+-----+----+-----+----+------------------+----------+--------------+
| Ma  | IP | 1   |    | No adverse       | 14 days  | Rhodes et    |
| rmo |    | 000 |    | effects          |          | al. (1986)   |
| set |    |     |    |                  |          |              |
+-----+----+-----+----+------------------+----------+--------------+
| Rat | IV | 62  |    | No adverse       | 18 days  | Baxter       |
|     |    |     |    | effects          |          | (2000)       |
+-----+----+-----+----+------------------+----------+--------------+
| Rab | IV | 62  |    | No adverse       | 28 days  | Baxter       |
| bit |    |     |    | effects          |          | (2000)       |
+-----+----+-----+----+------------------+----------+--------------+
| Rat | IV | 60  | 3  | Testicular       | 21 days  | AdvaMed      |
|     |    |     | 00 | atrophy,         |          | (2001)       |
|     |    |     |    | decrease in      |          |              |
|     |    |     |    | diameter of      |          |              |
|     |    |     |    | seminiferous     |          |              |
|     |    |     |    | tubules and      |          |              |
|     |    |     |    | depletion of     |          |              |
|     |    |     |    | germinal cells   |          |              |
|     |    |     |    | in testes        |          |              |
+-----+----+-----+----+------------------+----------+--------------+
| Rat | IV | 25  | 2  | Sertoli cells    | 10 days  | Sjoberg et   |
|     |    |     | 50 | vacuolization    |          | al.          |
|     |    |     |    | and spermatocyte |          | (1985a,b)    |
|     |    |     |    | degeneration     |          |              |
+-----+----+-----+----+------------------+----------+--------------+
| Dog | IV | 100 |    | No adverse       | 28 days  | Rutter       |
|     |    |     |    | effects          |          | (1973)       |
+-----+----+-----+----+------------------+----------+--------------+

**Developmental effects observed following parenteral administration of
DEHP to experimental animals**

  --------- ------- ---------- ---------- ------------------- -------------- ---------------
  Species   Route   NOAEL^1^   LOAEL^2^   Effect              Experimental   Study
                                                              Design         

  Rat       IP                 1000       Reduced fetal       Administered   Singh et al.
                                          weight              on GD 5, 10    (1972)
                                                              and 15         

  Rat       IP      1000       2000       Increased incidence Administered   Singh et al.
                                          of gross fetal      on GD 5, 10,   (1972)
                                          abnormalities       and 15         

  Mice      IP                 50         Increased incidence Administered   Tomita et al.
                                          of mid-ventral      once on GD     (1986)
                                          white spot          10.5           

  Mice      IV      1.25                  No adverse effects  Administered   Petersen et al.
                                                              once either on (1975)
                                                              GD2 or GD7     

  Rat       IV      1.25                  No teratogenic      Administered   Petersen et al.
                                          effects             once eight     (1975)
                                                              days following 
                                                              breeding       

  Rat       IV      3.5                   No teratogenic      Administered   Lewandowski et
                                          effects             on GD 6-15     al. (1980)

  Rat       IV      91.7       164.8      Reduced body weight Postnatal      Greener et al.
                                          gain and increased  exposure to    (1987)
                                          liver weight        3-day-old rat  
                                                              pups for 18    
                                                              consecutive    
                                                              days           
  --------- ------- ---------- ---------- ------------------- -------------- ---------------

**Cardiovascular** **effects observed following parenteral
administration of DEHP to experimental animals**

# 

+-------------+--------+------+------------+----------+--------------+
| **Study**   | **Spe  | *    | **F        | **Dose** | **Effect**   |
|             | cies** | *Rou | requency** |          |              |
|             |        | te** |            | **(mg/k  |              |
|             |        |      |            | g/day)** |              |
+-------------+--------+------+------------+----------+--------------+
| Rubin and   | Rat    | IV   | Single     | 40       | Fall in      |
| Chang       |        |      | dose       |          | arterial     |
| (1978)      |        |      |            |          | blood        |
|             |        |      |            |          | pressure     |
+-------------+--------+------+------------+----------+--------------+
| Calley et   | Rabbit | IV   | Single     | 300      | Fall in      |
| al. (1966)  |        |      | dose       |          | arterial     |
|             |        |      |            |          | blood        |
|             |        |      |            |          | pressure     |
+-------------+--------+------+------------+----------+--------------+
| Miyahara et | Rabbit | IV   | Single     | 500      | Fall in      |
| al. (1973)  |        |      | dose       |          | arterial     |
|             |        |      |            |          | blood        |
|             |        |      |            |          | pressure and |
|             |        |      |            |          | heart rate   |
+-------------+--------+------+------------+----------+--------------+

**References for Annex B**

Agarwal, D.K., Lawrence, W.H., and Turner, J.E. (1989). Effects of
parenteral di(2-ethyl­hexyl) phthalate (DEHP) on gonadal biochemistry,
pathology, and reproductive performance of mice. J Toxicol Environ
Health, 26:39-59.

Baxter (2000) Histopathological evaluation of testes from neonatal male
rats and rabbits treated with saline or approximately 62 mg/kg
Di-(2-Ethylhexyl)Phthalate (DEHP) in 4% Bovine Serum Albumin (BSA)
During Postnatal Days 3-21 (Rats) or 14-42 (Rabbits). Study number
TP062830535.

AdvaMed (2001) 21-Day repeat dose male reproductive tract study of
di(2-ethylhexyl)phthalate (DEHP) administered either intravenously or
orally to rats starting at neonatal age 3-5 days, with satellite
recovery group through 90 days of age. Study number 11947.

Curto, K.A., and Thomas, J.A. (1982). Comparative effects of
diethylhexyl phthalate or monoethylhexylphthalate on male mouse and rat
reproductive organs. Toxicol Appl Toxicol, 62:121-125.

Douglas, G.R., Hugenholtz, A.P., and Blakey, D.H. (1986). Genetic
toxicology of phthalate esters: mutagenic and other genotoxic effects.
Environ Health Perspect, 65:255-262.

Garvin PJ, Schmidt JG, Wallin RF (1976) Safety evaluation of plasma
solutions of Di-2ethylhexyl phthalate injected intravenously in rats.
Toxicol Appl Pharmacol. 37(1):99.

Greener, Y., Gillies, B., Wienckowski, D., Schmitt, D., Woods, E., and
Youkilis, E. (1987). Assessment of the safety of chemicals administered
intravenously in the neonatal rat. Teratol. 35:187-194.

Jacobson, M.S., Kevy, S.V., and Grand, R.J. (1977). Effects of a
plasticizer leached from polyvinyl chloride on the subhuman primate: a
consequence of chronic transfusion therapy. J Lab Clin Med,
89:1066-1079.

Komitowski, D., Schmezer, P., Schmitt, B., Muto, S. (1986). Image
analysis of hepatocyte nuclei in assessing di(2-ethylhexyl)phthalate
effects eluding detection by conventional microscopy. Toxicology,
Oct;41(1):11-19.

Leber, H.W., and Uviss, T. (1979). Influence of the plasticiser
di-2-ethylhexyl-phthalate on drug metabolising enzymes in the liver of
uraemic rats. Proc Eur Dial Transplant Assoc, 16:232-237.

Lewandowski, M., Fernandes, J., and Chen, T.S. (1980). Assessment of the
teratogenic potential of plasma-soluble extracts of diethyhexyl
phthalate plasticized polyvinyl chloride plastics in rats. Toxicol Appl
Pharmacol, 54:141-147.

Nair KG, Deepadevi KV, Arun P, Kumar VM, Santhosh A, Lekshmi LR, Kurup
PA Toxic effect of systemic administration of low doses of the
plasticizer di-(2-ethyl hexyl) phthalate \[DEHP\] in rats. Indian J Exp
Biol 1998 Mar;36(3):264-72.

Petersen SV, Lyman DJ, Roll DB, Swinyard EA (1975) Toxicology of Plastic
Devices having Contact with Blood. NTIS Report (PB-250 102).

Pollack GM, Shen DD, Dorr MB (1989) Contribution of metabolites to the
route- and time-dependent hepatic effects of di-(2-ethylhexyl)phthalate
in the rat. J Pharmacol Exp Ther 1989 Jan;248(1):176-81.

Rathinam K, Srivastava SP, Seth PK Hepatic studies of intraperitoneally
administered tris(2-ethyl hexyl)trimellitate (TOTM) and di(2-ethyl
hexyl)phthalate in rats. J Appl Toxicol 1990 Feb;10(1):39-41.

Rhodes, C., Orton, T.C., Pratt, I.S., Batten, P.L., Bratt, H., Fackson,
S.J., and Elcombe, C.R. (1986). Comparative pharmacokinetics and
subacute toxicity of di-(2-ethylhexyl) phthalate (DEHP) in rats and
marmosets: extrapolation of effects in rodents to man. Environ. Health
Perspect. 65, 299-308.

Rubin R and Chang J (1978) Effect of the intra venous administration of
the solubilized plasticizer di(2-ethylhexyl) phthalate on the lung and
on survival of transfused rats. Toxicol Appl Pharmacol. 45 (1):230.

Rutter H. (1973) Toxicology of plastic devices having contact with
blood. Acute and subacute toxicity of di(2-ethylhexyl) phthalate in
dogs. Annual report for the period June 29, 1972 -- October 1, 1973.
Contract No. NIH-NHLI-72-2991B. Available through NTIS with order number
PB224-376.

Rutter H. (1975) Three-week intravenous administration in dog of
di(2-ethylhexyl)phthalate. Report for the National Heart and Lung
Institute. Available through NTIS with order number PB-244-262.

Schulz CO, Rubin RJ, Hutchins GM (1975) Acute lung toxicity and sudden
death in rats following the intravenous administration of the
plasticizer, di(2-ethylhexyl)phthalate, solubilized with Tween
surfactants. Toxicol Appl Pharmacol. 33(3):514-25.

Seth PK, Srivastava SP, Mushtaq M, Agarwal DK, Chandra SV (1979) Effect
of di-(2-ethylhexyl) phthalate on rat liver injured by chronic carbon
tetrachloride treatment. Acta Pharmacol Toxicol (Copenh) 44(3):161-7.

Singh AR, Lawerence WH, Autian J (1972) Teratogenicity of a group of
phthalate esters in rats. J. Pharm. Sci. 61:51-55.

Sjoberg, P., Bondesson, U., Sedin, G. and Gustafsson, J. (1985a). Eur.
J. Clin. Invest. 15, 430-436.

Sjöberg, P., Lindquist, N.G., Montin, G., and Plöen, L. (1985b). Effects
of repeated intra­venous infusions of the plasticizer di-(2-ethylhexyl)
phthalate in young male rats. Arch. Toxicol. 58, 78-83.\
\
Srivastava SP, Seth PK, Agarwal DK (1975) Biochemical effects of
di-2-ethylhexyl phthalate. Environ Physiol Biochem 5(3):178-83.

Tomita, I., Nakamura, Y., Yagi, Y., and Tutikawa, K. (1986). Fetotoxic
effects of mono-2-ethylhexyl phthalate (MEHP) in mice. Environ. Health
Perspect. 65, 249-254.

**Annex C. Aggregate Safety Assessment for Coexposure**

**to DEHP and MEHP**

In addition to conversion of DEHP to MEHP in the body, DEHP can be
converted to MEHP exogenously by lipases in stored plasma or blood or by
hydrolysis in stored and heated IV fluid.

As a result, some of the DEHP that is released into stored blood,
plasma, or IV fluids will be converted to MEHP before reaching the
patient. Previous safety assessments have only explicitly accounted for
exposure to DEHP; however, it is important to also account for exposure
to MEHP, especially since MEHP is more potent than DEHP in producing
adverse reproductive effects.

# C.1 Mixtures Risk Assessment Approaches

In risk assessment, two approaches have been developed to assess the
combined potency of constituents of chemical mixtures: the Hazard Index
Approach and the Relative Potency Approach.

# C.1.1 Hazard index approach 

The Hazard Index approach is described in ISO/DIS 10993-17 as follows:

> If the compounds being leached from a device exert their effects via a
> common toxicological mechanism of action or are structurally similar
> to one another (e.g., phthalate esters, acrylates, methacrylates), and
> the dose of these compounds received by a patient is well below the
> respective TI value for each compound, it can be assumed that any
> effects will occur in an additive fashion, that is, the combined
> effects of two or more agents is equal to the sum of the effects of
> each agent given alone. As a result, a Hazard Index (HI) approach can
> be used to estimate the likelihood that adverse effects will occur
> following exposure to the mixture. A HI can be calculated as follows:
>
> $$\text{HI = }\sum_{\text{i = 1}}^{n}\frac{\text{dose}_{{}^{i}}}{\text{TI}_{{}^{i}}}$$
>
> Where n is the number of components of the mixture and dose of each
> constituent received by the patient.

Use of the HI approach would be appropriate for estimating the combined
potency of MEHP and DEHP since they exert their effect via a common
mechanism of action; however, there are insufficient toxicity data to
derive a TI for MEHP. As a result, use of the HI approach for combined
exposures to DEHP and MEHP is impractical.

# C.1.2 Relative Potency Approach

The relative potency approach is typically used to estimate the combined
potency of complex mixtures of dioxins and dioxin-like compounds,
polycyclic aromatic hydrocarbons, and cholinesterase-inhibiting
pesticides, but has also recently been proposed as a means to estimate
the combined potency of complex mixtures of phthalate esters (Gray et
al., 2000). To estimate the potency of the mixture from it's individual
chemical components using this approach, it is necessary to define the
potency of each of the components relative to an index compound,
typically the constituent for which we have the largest body of
scientific data of acceptable quality. The total concentration the
mixture components, expressed relative to an index compound, can be
derived as follows:

*C~mixture~ = C~index~ + Σ \[RPF~i~ x C ~i~ \]*

where C~mixture~ = total mixture concentration expressed in terms of the
index compound, C~index~ = concentration of the index compound in
mixture, C~i~ = concentration of the mixture component~i~ , and RPF~i~ =
the proportionality constant relative to the index compound for the
mixture component~i~ . With regard to DEHP and MEHP, DEHP will serve as
the index compound and the concentration of MEHP will be expressed in
terms of DEHP equivalents.

The relative potency values are also known as Toxic Equivalency Factors
or TEFs. In their guidance for conducting health risk assessment of
chemical mixtures, the EPA (1999) has differentiated TEFs from RPFs,
based on the criteria described in Table C-1.

## **Table C-1. Differences Between TEF and RPF**

+-----------------------------------+-----------------------------------+
| ## **TEF**                        | **RPF**                           |
+-----------------------------------+-----------------------------------+
| TEF apply to all heath endpoints  | RPF may be limited to specific    |
|                                   | health                            |
|                                   |                                   |
|                                   | endpoints                         |
+-----------------------------------+-----------------------------------+
| TEF apply to all exposure routes  | RPF may be limited to specific    |
|                                   | routes                            |
+-----------------------------------+-----------------------------------+
| Implies greater precision due to  | Implies less precision due to     |
| higher                            | lower                             |
|                                   |                                   |
| quality/more abundant data        | quality/fewer data                |
+-----------------------------------+-----------------------------------+

As discussed below, the relative potency factors for MEHP and DEHP are
primarily based on a specific health endpoint (testicular toxicity), are
limited to specific routes (parenteral) and are associated with some
uncertainty. As a result, it may be more appropriate to refer to the
MEHP:DEHP relative potency value as an RPF, using the EPA criteria.

### C.2 Derivation of an RPF for MEHP in Terms of DEHP Equivalents

######## C.2.1 Do MEHP and DEHP meet the criteria for RPF derivation?

Specific criteria must be met before an RPF can be derived for any set
of compounds. The chemical constituents of the mixture should produce
similar toxicologic effects and the mechanism by which they produce
these effects should be the same. Also, the compounds should occur as a
mixture in the exposure media. Finally, RPF approach assumes additivity
of dose. With regard to MEHP and DEHP, it is well known that they
produce similar effects on the testes and do so via the same mechanism.
As discussed in Section 2.0, both compounds are found in stored blood
and plasma and stored IV solutions. The dose additivity assumption has
not been explicitly validated for MEHP and DEHP; however, since MEHP has
been shown to be the active metabolite of DEHP in the testes (Gray et
al., 1982; Gray and Gangolli, 1986; Oishi, 1993), it can safety be
assumed that doses of DEHP and MEHP will be additive, since DEHP is
thought to exert its effects following conversion to MEHP.

# C.2.2 Selection of an RPF value for MEHP

Although it has been demonstrated in numerous studies that MEHP is more
potent than DEHP, a challenge exists in selecting an RPF to
quantitatively (or semi-quantitatively) represent this potency
difference. Ideally, the RPF for MEHP would be derived from a study in
which dose-response curves for testicular effects were derived following
IV administration of both compounds individually. Unfortunately, such a
study has not been conducted. Alternately, an RPF for MEHP can be
derived using data in the published literature on the relative potency
of MEHP and DEHP following oral and IP administration and in *in vitro*
studies.

***Relative potency of MEHP and DEHP in in vitro studies***

The relative potency of MEHP:DEHP in *in vitro* studies without a
metabolic activating system may not accurately reflect the relative
potency of these compounds *in vivo* following parenteral
administration; however, these studies do provide an opportunity to
compare the relative pharmacodynamic potency of the compounds without
considering the bioactivation of one and the detoxification of the
other. As shown in Table C-2, the relative *in vitro* potency of these
compounds ranges from \> 10 to \>1000, depending on the endpoint and
study.

There are numerous other studies in the literature that underscore the
increased potency of MEHP compared to DEHP in producing effects in
testicular cells in vitro, however, the results of these studies do not
lend themselves to quantitative determination of an RPF for MEHP. For
example, Grasso et al. (1983) found that 100 μM MEHP inhibited FSH
binding to cultured rat Sertoli cells, whereas incubation with 100 μM
DEHP had no effect on FSH binding. Also, Gangolli (1982) showed that 200
μM MEHP produced dissociation of germ cells from Sertoli cells in
culture, while the same concentration of DEHP did not. Finally, Moss et
al. (1988) reported that MEHP stimulated lactate production in Sertoli
cell cultures but DEHP had no such effect.

***Relative potency of MEHP and DEHP following oral administration***

As shown in Table C-2, the relative potency of MEHP:DEHP for testicular
effects ranges from about 3 to 10 following oral administration of the
compounds. Relative potency values derived from oral studies are likely
to underestimate the relative potency of MEHP and DEHP following
parenteral exposure, since DEHP will be more potent following oral vs.
parenteral exposure, because it is bioactivated in the gut, and the
potency of MEHP will be less following oral exposure, compared to
parenteral, because it is detoxified in the gut. Consequently, in oral
studies, the value for the denominator (DEHP potency) goes up and the
value for the numerator (MEHP potency) goes down.

### Table C-2. Relative MEHP/DEHP potency for testicular effects

+------------+-------+----------------------------+-------------------+
| **Relative | **Ro  | **Comments**               | **Study**         |
| potency**  | ute** |                            |                   |
|            |       |                            |                   |
| **M        |       |                            |                   |
| EHP/DEHP** |       |                            |                   |
+------------+-------+----------------------------+-------------------+
| \>10       | In    | MEHP inhibited state 3     | Oishi et al.      |
|            | Vitro | oxygen consumption in      | (1990)            |
|            |       | testicular mitochondria at |                   |
|            |       | doses as low as 0.065      |                   |
|            |       | mumole/ml, whereas DEHP    |                   |
|            |       | doses up to 0.65 mumole/ml |                   |
|            |       | did not                    |                   |
+------------+-------+----------------------------+-------------------+
| \> 100     | In    | 0.1 μM MEHP suppressed     | Li et al. (1998)  |
|            | Vitro | basal Sertoli cell         |                   |
|            |       | proliferation, whereas 10  |                   |
|            |       | μM DEHP did not            |                   |
+------------+-------+----------------------------+-------------------+
| \> 1000    | In    | MEHP conc. As low as 1 μM  | Sjoberg et al.    |
|            | Vitro | caused germ cell           | 1986              |
|            |       | detachment after 48 hours, |                   |
|            |       | whereas DEHP conc. as high |                   |
|            |       | as 1000 μM did not.        |                   |
+------------+-------+----------------------------+-------------------+
| 3.5        | Oral  | Reduction in relative      | Teirlynck et al.  |
|            |       | testes weight, tubular     | (1988)            |
|            |       | diameter, and testicular   |                   |
|            |       | zinc, along with histopath |                   |
|            |       | scores, was similar        |                   |
|            |       | following administration   |                   |
|            |       | of a single dose of 2.8    |                   |
|            |       | g/kg DEHP or 0.8 g MEHP    |                   |
+------------+-------+----------------------------+-------------------+
| 10         | Oral  | DEHP caused an increased   | Tomita et al.     |
|            |       | chromosomal aberration     | (1982)            |
|            |       | rate at 3750 mg/kg,        |                   |
|            |       | whereas MEHP caused same   |                   |
|            |       | effect at 375 mg/kg        |                   |
+------------+-------+----------------------------+-------------------+
| 2          | IP    | DEHP administration        | Curto and Thomas  |
|            |       | resulted in reduced zinc   | (1982)            |
|            |       | in anterior prostate at 50 |                   |
|            |       | mg/kg, whereas MEHP        |                   |
|            |       | produced same effect       |                   |
|            |       | following injection of 25  |                   |
|            |       | mg/kg                      |                   |
+------------+-------+----------------------------+-------------------+

The relative potency of MEHP:DEHP for other endpoints may inform the
process of developing a RPF for these compounds with regard to
reproductive effects. The results of Shiota and Mima (1985) suggest that
MEHP is 20-fold more potent than DEHP in producing maternal toxicity in
pregnant ICR mice following gavage administration and 80-fold more
potent following IP administration (Table C-3).

**Table C-3. Relative potency of DEHP and MEHP in producing maternal
effects in pregnant ICR mice (from Shiota and Mima, 1985)**

+-----------------+-----------------+-----------------+-----------------+
| **Route**       | **Dose          |                 | **Relative      |
|                 | (mg/kg/day)**   |                 | Potency**       |
|                 |                 |                 |                 |
|                 |                 |                 | **MEHP/DEHP**   |
+-----------------+-----------------+-----------------+-----------------+
|                 | **MEHP**        | **DEHP**        |                 |
+-----------------+-----------------+-----------------+-----------------+
| Gavage          |                 |                 |                 |
+-----------------+-----------------+-----------------+-----------------+
| NOAEL           | 50              | 1000            | 20              |
+-----------------+-----------------+-----------------+-----------------+
| LOAEL           | 100             | 2000            | 20              |
+-----------------+-----------------+-----------------+-----------------+
|                 |                 |                 |                 |
+-----------------+-----------------+-----------------+-----------------+
| Intraperitoneal |                 |                 |                 |
+-----------------+-----------------+-----------------+-----------------+
| NOAEL           | 50              | 4000            | 80              |
+-----------------+-----------------+-----------------+-----------------+
| LOAEL           | 100             | 8000            | 80              |
+-----------------+-----------------+-----------------+-----------------+

The results of Yagi et al. (1980) and Tomita et al. (1982) suggest that
MEHP is approximately an order of magnitude more potent than DEHP in
producing fetal malformations, increased fetal death and decreased fetal
weight following administration by gavage to ddY-Slc mice on gestational
day 7 (LOAEL of 104 mg/kg/day for MEHP vs. 984 mg/kg/day for DEHP).

### *Relative potency of MEHP and DEHP following parenteral administration*

Few studies are available to assess the relative potency of parenterally
administered MEHP and DEHP, especially for testicular effects. Curto and
Thomas (1982) reported that the relative potency of DEHP and MEHP
depends on the endpoint being examined. For example, rats injected IP
with 50 mg/kg MEHP experienced a 37% decrease in zinc levels in the
anterior prostate, an effect produced following administration of 100
mg/kg DEHP, suggesting a 2-fold difference in potency. However, the same
dose of DEHP resulted in reduced levels of zinc in the testes, whereas
the 50 mg/kg dose of MEHP did not, suggesting that DEHP is more potent
in producing this effect.

The only other results available for determining the relative potency of
MEHP and DEHP following parenteral exposure are those of Shiota and Mima
(1985) and are described in Table C-2.

# C.3 Selection of an RPF for MEHP

The results of *in vitro* studies suggest that MEHP could be as much as
1000-fold more potent than DEHP in producing adverse effects on
testicular cells; however, it's not clear how relevant the *in vitro*
relative potency values are for the *in vivo* state, since DEHP can be
bioactivated in the body and MEHP can be detoxified. In contrast, MEHP
is about 3- to 10-fold more potent than DEHP in producing adverse
testicular effects following oral administration, and 20-fold more
potent in producing developmental effects (in one study). Similarly,
it's not clear how these values reflect the relative potency following
parenteral administration, due to bioactivation of DEHP and
detoxification of MEHP in the gut. Based on the results of the few
parenteral studies of MEHP:DEHP relative potency, MEHP could be slightly
more potent than DEHP, less potent than DEHP (for some endpoints) or
could be as much as 80-fold more potent (for developmental effects). The
wide range of the relative potency values for MEHP and DEHP underscore
the difficulty in selecting an RPF for MEHP to use in a cumulative risk
assessment of these compounds. Since the weight of evidence suggests
that MEHP is at least an order of magnitude more potent than DEHP to
testicular cells, it is reasonable to assign a provisional RPF value of
10 to MEHP until better data are available on the relative potency of
MEHP and DEHP following parenteral exposure. Consequently, it will be
assumed that a 1 mg/kg dose of DEHP will produce the same effects in the
testes as a 10 mg/kg dose of MEHP, for the purpose of deriving
DEHP-equivalents. Designation of an RPF for MEHP suggesting that the
relative potency of this compound is "about an order of magnitude"
greater than DEHP following parenteral exposure is also intended to
emphasize the lack of precision in the value and the uncertainty
selecting the value.

**C.4 Total MEHP and DEHP Dose in terms of DEHP equivalents**

Using the data on the dose of DEHP and MEHP received by patients
undergoing various procedures (Section 2.0), it is possible to derive a
total dose of DEHP and MEHP in terms of DEHP equivalents (Table C-4).

**Table C-4. Total dose of DEHP and MEHP in terms of DEHP equivalents**

+----------------------+----------+------------+----------------------+
| **Procedure**        | **DEHP   | **MEHP     | **DEHP equivalent    |
|                      | dose**   | dose**     | dose**               |
|                      |          |            |                      |
|                      | **(mg/k  | **(mg      | **(mg/kg/day)**      |
|                      | g/day)** | /kg/day)** |                      |
+----------------------+----------+------------+----------------------+
| **Infusion of IV     | 0.005    | 0.013      | 0.135                |
| crystalloid          |          |            |                      |
| solutions**          |          |            |                      |
+----------------------+----------+------------+----------------------+
|                      |          |            |                      |
+----------------------+----------+------------+----------------------+
| #                    |          |            |                      |
| ## Blood transfusion |          |            |                      |
+----------------------+----------+------------+----------------------+
| Trauma patient       | 8.5      |            |                      |
+----------------------+----------+------------+----------------------+
| Transfusion/ECMO     | 3.0      | 2.0        | 23                   |
|                      |          |            |                      |
| (adult)              |          |            |                      |
+----------------------+----------+------------+----------------------+
| Exchange transfusion | 22.6     | 0.68       | 29.4                 |
|                      |          |            |                      |
| (neonate)            |          |            |                      |
+----------------------+----------+------------+----------------------+
| Replacement          | 0.3      | 0.0043     | 0.34                 |
|                      |          |            |                      |
| Transfusion          |          |            |                      |
| (neonate)            |          |            |                      |
+----------------------+----------+------------+----------------------+
|                      |          |            |                      |
+----------------------+----------+------------+----------------------+
| ### Ca               |          |            |                      |
| rdiopulmonary bypass |          |            |                      |
+----------------------+----------+------------+----------------------+
| CABG                 | 1        | 0.1        | 2                    |
+----------------------+----------+------------+----------------------+
| Orthotopic heart     | 0.3      | 0.03       | 0.6                  |
| transplant           |          |            |                      |
+----------------------+----------+------------+----------------------+
| Artificial heart     | 2.4      | 0.26       | 5                    |
| transplant           |          |            |                      |
+----------------------+----------+------------+----------------------+

It is not known whether DEHP is converted exogenously to MEHP in stored
TPN or enteral nutrition solutions.

Although both DEHP and MEHP have been detected and quantified in
patients undergoing hemodialysis, it is not clear how much of the MEHP
was formed *in vivo* and how much, if any, was formed exogenously in the
hemodialysis circuit.

The values for DEHP equivalent dose were used to derive TI/Dose ratios
for aggregate exposure to DEHP and MEHP (Table C-5).

**Table C-5. Total dose of DEHP and MEHP in terms of DEHP equivalents**

+-----------------------+----------------------+----------------------+
| **Procedure**         | **TI/Dose ratio**    |                      |
+-----------------------+----------------------+----------------------+
|                       | DEHP alone           | DEHP + MEHP          |
+-----------------------+----------------------+----------------------+
| **Infusion of IV      | 120                  | 4                    |
| crystalloid           |                      |                      |
| solutions**           |                      |                      |
+-----------------------+----------------------+----------------------+
|                       |                      |                      |
+-----------------------+----------------------+----------------------+
| ### Blood transfusion |                      |                      |
+-----------------------+----------------------+----------------------+
| Transfusion/ECMO      | 0.2                  | 0.03                 |
|                       |                      |                      |
| (adult)               |                      |                      |
+-----------------------+----------------------+----------------------+
| Exchange transfusion  | 0.02                 | 0.02                 |
|                       |                      |                      |
| (neonate)             |                      |                      |
+-----------------------+----------------------+----------------------+
| Replacement           | 2                    | 2                    |
|                       |                      |                      |
| Transfusion (neonate) |                      |                      |
+-----------------------+----------------------+----------------------+
|                       |                      |                      |
+-----------------------+----------------------+----------------------+
| ### C                 |                      |                      |
| ardiopulmonary bypass |                      |                      |
+-----------------------+----------------------+----------------------+
| CABG                  | 0.6                  | 0.3                  |
+-----------------------+----------------------+----------------------+
| Orthotopic heart      | 2                    | 1                    |
| transplant            |                      |                      |
+-----------------------+----------------------+----------------------+
| Artificial heart      | 0.3                  | 0.1                  |
| transplant            |                      |                      |
+-----------------------+----------------------+----------------------+

As shown in Table C-5, the procedures with TI/Dose ratios \>1 when only
DEHP was taken into account continued to have TI/Dose ratios \>1 when
exposure to both DEHP and MEHP was accounted for.

# References for Annex C

Curto, K.A., and Thomas, J.A. (1982). Comparative effects of
diethylhexyl phthalate or monoethylhexylphthalate on male mouse and rat
reproductive organs. Toxicol Appl Toxicol, 62:121-125.

EPA (1999) Guidance for Conducting Health Risk Assessment for Chemical
Mixtures <http://www.epa.gov/NCEA/pdfs/mixtures.pdf>

Gangolli, S.D. (1982). Testicular effects of phthalate esters. Environ
Health Perspect, 44:77-84.

Grasso, P., Heindel, J.J., Powell, C.J., and Reichert, Jr., L.E. (1993).
Effects of mono(2-ethyl­hexyl) phthalate, a testicular toxicant, on
follicle-stimulating hormone binding to membranes from cultured rat
sertoli cells. Biol Reprod, 48:454-459.

Gray, T.J.B , and Gangolli, S.D. (1986). Aspects of the testicular
toxicity of phthalate esters. Environ Health Perspect, 65:229-235.

Gray, T.J.B., Rowland, I.R., Foster, P.M.D., and Gangolli, S.D. (1982).
Species differences in the testicular toxicity of phthalate esters.
Toxicol Lett, 11:141-147.

Gray LE Jr, Ostby J, Furr J, Price M, Veeramachaneni DN, Parks L. (2000)
Perinatal exposure to the phthalates DEHP, BBP, and DINP, but not DEP,
DMP, or DOTP, alters sexual differentiation of the male rat. Toxicol
Sci. 58(2):350-65.

Li LH, Jester WF Jr, Orth JM. (1998) Effects of relatively low levels of
mono-(2-ethylhexyl) phthalate on cocultured Sertoli cells and gonocytes
from neonatal rats. Toxicol Appl Pharmacol. 153(2):258-65.

Moss, E.J., Cook, M.W., Thomas, L.V., and Gray, T.J.B. (1988). The
effect of mono-(2-ethyl) ­phthalate and other phthalate esters on lactate
production by Sertoli cells in vitro. Toxicol. Lett. 40, 77-84.

Oishi, S. (1990). Effects of phthalic acid esters on testicular
mitochondrial functions in the rat. Arch. Toxicol. 64, 143-147.

Oishi, S. (1993). Strain differences in susceptibility to
di-2-ethylhexyl phthalate-induced testic­ular atrophy in mice. Toxicol.
Lett. 66, 47-52.

Shiota, K. and Mima, S. (1985). Assessment of the teratogenicity of
di(2-ethylhexyl) phtha­late and mono-(2-ethylhexyl) phthalate in mice.
Arch. Toxicol. 56, 263-266.

Sjöberg, P., Bondesson, U., Gray, T.J.B., and Plöen, L. (1986). Effects
of di-(2-ethylhexyl) phthalate and five of its metabolites on rat testis
in vivo and in vitro. Acta Pharmacol. Toxicol. 58, 225-233.

Teirlynck, O., Kaufman, J.M., Bogaert, M.G., and Roels, H. (1988).
Testicular toxicity induc­ed by single dosing of di- and
mono-(2-ethylhexyl) phthalate in the rat. Toxicol. Lett. 40, 85-91.

Tomita, I., Nakamura, Y., Yagi, Y., and Tutikawa, K. (1982).
Teratogenicity/fetotoxicity of DEHP in mice. Environ. Health Perspect.
45, 71-75.

Yagi, Y., Nakamura, Y., Tomita, I., Tsuchikawa, K., and Shimoi, N.
(1980). Teratogenic potential of di- and mono-(2-ethylhexyl) phthalate
in mice. J. Environ. Pathol. Toxicol. 4, 533-544.

# Annex D. Nonsystemic Effects

Systemic effects (effects seen at a organ or tissue site distant from
the portal of exposure or injection site) serve as the basis for
derivation of TI values; however, DEHP produces other effects, either
locally upon administration or *ex vivo* that may be clinically
important as well. Although these effects cannot serve as the basis for
derivation of a TI value, they may be important to consider during the
risk management phase of the assessment.

**D.1 Role of DEHP in mediating the poor hemocompatibility of
DEHP-plasticized PVC**

The thrombogenic nature of PVC materials is well known (Yianni, 1995).
As discussed below, there is substantial evidence that the extent of
platelet aggregation is due to the presence of DEHP in the material and
not the PVC itself. In addition, complement activation, a process
associated with adverse hematological effects, is greater following
exposure of blood to DEHP-plasticized PVC than to other polymers. Each
of these effects, increased platelet aggregation and complement
activation, can have adverse clinical consequences in patients
undergoing various medical procedures.

Kim et al. (1976) found that the absorption of γ-globulin and fibrinogen
was greater on phthalate-contaminated PVC surfaces than surfaces that
had been cleaned by methanol. The presence of these proteins on the
surface of PVC induces platelet adhesion to the surface. Jones et al.
(1989) found that platelet adhesion was greater on PVC plasticized with
DEHP than PVC plasticized with either trioctyl trimellitate or polymeric
adipate. Zhao and Courtney (1999) recently confirmed the findings of
Jones et al. (1989). These investigators found greater fibrinogen
adsorption onto DEHP-plasticized PVC than onto unplasticized PVC.
Notable are their findings that the extent of fibrinogen adsorption
increases as a function of the level of DEHP on the surface of the
polymer. These results lead the authors to conclude that: "...reduction
in the amount of plasticizer at the surface \[of the polymer\] improves
the blood compatibility of plasticized polyvinyl chloride, and the
influence of blood is due primarily to the plasticizer rather than the
polyvinyl chloride."

It is interesting to note that the adhesion of fungus to PVC was also
enhanced by the presence of plasticizers (DEHP or dioctyl adipate) in
the polymer (Webb et al., 1999).

Reduced platelet adhesion has been observed on some alternatives to
DEHP-plasticized PVC. For example, Lee et al. (1999) found that the
adhesion of platelets on PVC film was significantly reduced by the
incorporation of polyethylene oxide (PEO)-containing amphiphilic block
copolymer additives to the PVC. Coating the blood contact surface of PVC
materials with various substances also improves the hemocompatibility of
the tubing (Kicheva et al., 1995).

Platelet adhering to polymer surfaces may initiate a sequence of events
leading to thrombus development on the polymer surface. Release of
thrombi into the blood stream can have clinical consequences. For
example, microemboli released from ECMO circuits are thought to be
responsible for infarcts in the brain, lung and kidney of patients
undergoing ECMO therapy (Fink et al., 1989). Also, neurological
complications following cardiopulmonary bypass are thought to be due to
the release of microemboli (Taylor et al., 1999), although many of these
emboli may be air bubbles, not thrombi released from a PVC surface. The
use of in-line filters will obviously reduce the risk of clinical
sequelae associated with the release of microemboli from PVC surfaces.

Complement activation on the surface of polymeric materials is
associated with adverse hematological effects. Higher levels of
complement (C3a) and FXII-like activity were observed on
DEHP-plasticized PVC than on regenerated cellulose (Cuprophan) or an
acrylonitrile-allyl sulphonate copolymer (AN69S) (Lamba et al., 2000).
To put these results into perspective, the authors of this study note:

> The complement generating capacity of PVC/DEHP is greater than that of
> Cuprophan, a membrane that is regarded as a high complement activator.
> Therefore, the role of the blood tubing in determining the
> biocompatibility of extracorporeal procedures must be acknowledged.
> ... There is evidence that the surface of medical grade PVC is rich in
> plasticizer \[28,29\], and thus, one may expect that plasticizer has
> the potential to influence the blood response.

Complement activation sets up a complex cascade of events involving
chemotaxis of leukocytes which can release cytokines and induce platelet
activation. These events are thought to play a role in the inflammatory
response seen in patients on CPB. As a result, DEHP is able to promote
complement activation on the surface of plasticized PVC, an event that
may have adverse clinical consequences.

Significantly less complement activation and platelet adherence occur on
heparin-coated PVC tubing (Wendel and Ziemer, 1999). Karle et al. (1997)
found that heparin coating of PVC tubing dramatically reduces the amount
of DEHP released from the tubing. Therefore, improved hemocompatibility
of heparin--coated tubing may be due, in part, to reduced DEHP on the
surface of the material. Consequently, heparin coating could be explored
as a means to block the ability of DEHP to promote the deposition of
protein, adhesion of platelets, and activation of complement on PVC.

# D.2 Role of DEHP in Mediating Drug Adsorption onto PVC Surfaces

Recommendations for the use of non-PVC tubing for the intravenous
administration of some drugs are intended to limit the amount of drug
adhering to the surface of the tubing, not to limit the dose of DEHP
received by the patient. Drug loss by binding to the surface of PVC
tubing or bags will limit the dose of the drug that will reach the
patient. Although drug loss is typically greater in PVC bags and tubing,
compared to bags and tubing made from alternate materials (e.g.,
polyethylene), it was only recently shown that the amount of drug loss
is correlated with the amount of leaching of DEHP from the tubing, at
least for cyclosporine (Yano et al., 2001). Consequently, the presence
of DEHP in PVC tubing may have important clinical consequences separate
from those associated with patient exposure to DEHP.

**D.3 Possible Role of DEHP in Producing Peritoneal Sclerosis**

Peritoneal sclerosis is a serious complication of peritoneal dialysis
therapy. Although factors such as the osmolarity, pH and lactate content
of the dialysis solution may contribute to the pathogenesis of
peritoneal sclerosis (Carozzi et al., 1993), several investigators have
postulated a role for DEHP in the pathogenesis of this condition (Gandhi
et al., 1980; Fracasso et al., 1993, 1999; Solary et al., 1986;
Nassburger and Arbin, 1987; Calo et al., 1993; Carozzi et al., 1993).

A recent study (Fracasso et al., 1999) demonstrated that peritoneal
sclerosis was produced in rats following intraperitoneal injection of a
DEHP dose of 0.05 mg/kg/day for 7 days. Since DEHP was injected neat,
the possibility exists that similar effects would not occur following
infusion of DEHP-containing dialysate. Dialysate stored in
DEHP-containing bags stimulated the proliferative capacity of peritoneal
fibroblasts, whereas dialysate stored in DEHP-free bags (Clear-Flex,
Bieffe) did not (Carozzi et al., 1993). It is reasonable to assume that
proliferation of peritoneal fibroblasts is an initial step in the
process leading to thickening or sclerosis of the peritoneal membrane.
The results of Carozzi et al. (1993) suggest that levels of DEHP in
dialysate stored in DEHP bags are sufficient to initiate the process of
peritoneal sclerosis.

Solary et al. (1986) described a case report in which a patient
undergoing peritoneal dialysis developed a culture-negative peritonitis
with a high eosinophil count following infusion of dialysate that had
been stored in PVC bags. The white blood cell count in the peritoneal
dialysis fluid fell dramatically following infusion of dialysate stored
in glass bottles, then increased again when PVC-stored dialysate was
used. The influx of eosinophils into the peritoneum could be in response
to an inflammatory reaction.

Mechanistic support exists for a role for DEHP in the pathogenesis of
peritoneal sclerosis in patients receiving peritoneal dialysis. Carozzi
et al. (1993) have shown that *in vitro* exposure of peritoneal T
lymphocytes and macrophages to peritoneal dialysis solution contained in
DEHP-containing PVC bags resulted in increased release of IL-1 and
interferon gamma and a decrease in release of prostaglandin E2, a
cytokine that inhibits collagen synthesis, as compared to exposure of
these cells to dialysis solution stored in DEHP-free bags (Clear-Flex,
Bieffe).

The work of Stabellini et al. (1998) further supports the ability of
DEHP to stimulate fibroblasts and produce fibrosis. These investigators
introduced either undiluted or diluted DEHP (10 μmol/ml) into a
previously created air pouch in rat subcutaneous tissue. Exposure to
DEHP produced hyperplastic changes and alterations to fibroblasts in the
subcutaneous tissue. It is also interesting to note that repeated
intraperitoneal injection of DEHP in rats results in a reduction in the
rate and extent of absorption of this compound from the peritoneal
cavity (Pollack et al., 1985). Reduced absorption could be caused by
thickening of the peritoneal membrane. Further, repeated IP injections
of DEHP in rats resulted in a diminished effect on microsomal activity
in the liver, as compared with a single IP injection (Agarwal et al.,
1982). This finding could also be explained by fibrosis of the
peritoneal membrane and reduced peritoneal absorption of the compound.

While the results of the above studies do not confirm a role for DEHP in
the etiology of peritoneal sclerosis in patients undergoing peritoneal
dialysis, they do nevertheless provide supporting evidence for a
contributory role for DEHP in this process. Although osmolarity, pH, and
lactate and glucose content of the dialysis solution are all factors
that have been associated with the pathogenesis of peritoneal sclerosis,
the results of the above studies suggest a possible contributory role
for DEHP.

The clinical significance of peritoneal sclerosis cannot be
underestimated, because patients with reduced dialytic capacity of the
peritoneal membrane must be switched to hemodialysis. As a result, any
role for DEHP in the etiology of this condition should be explored
further.

**References for Annex D**

Agarwal DK, Agarwal S, Seth PK (1982) Interaction of di-(2-ethylhexyl)
phthalate with the pharmacological response and metabolic aspects of
ethanol in mice. Biochem Pharmacol. 31(21):3419-23.

Calo L, Fracasso A, Cantaro S, Cozzi E, De Silvestro G, Plebani M,
Bazzato G, and Borsatti A (1993) Plasticizers induced mononuclear cells
interleukin 1 production: implications with peritoneal sclerosis. Clin
Nephrol. 40(1):57.

Carozzi S, Nasini MG, Schelotto C, Caviglia PM, Santoni O, and Pietrucci
A (1993) A biocompatibility study on peritoneal dialysis solution bags
for CAPD. Adv Perit Dial. 9:138-42.

Fink SM, Bockman DE, Howell CG, Falls DG, and Kanto WP (1989) Bypass
circuits as the source of thromboemboli during extracorporeal membrane
oxygenation. J Pediatr. 115(4):621-4.

Fracasso A, Calo L, Landini S, Morachiello P, Righetto F, Scanferla F,
Toffoletto P, Genchi R, Roncali D, Cantaro S, et al. (1993) Peritoneal
sclerosis: role of plasticizers in stimulating interleukin-1 production.
Perit Dial Int. 13 Suppl 2:S517-9.

Fracasso A, Baggio B, Ossi E, Del Prete D, Bonfante L, Bazzato G,
Gambaro G (1999) Glycosaminoglycans prevent the functional and
morphological peritoneal derangement in an experimental model of
peritoneal fibrosis. Am J Kidney Dis 33(1):105-10.

Gandhi VC, Humayun HM, Ing TS, Daugirdas JT, Jablokow VR, Iwatsuki S,
Geis WP, and Hano JE (1980) Sclerotic thickening of the peritoneal
membrane in maintenance peritoneal dialysis patients. Arch Intern Med.
140(9):1201-3.

Jones C, Courtney JM, Robertson LM, Biggs MS, and Lowe GD (1989)
Influence of plasticised poly(vinyl chloride) on platelet adhesion and
platelet aggregates. Int J Artif Organs 12(7):466-70.

Karle VA, Short BL, martin GR, Bulas DI, Getson PR, Luban NL, O'Brien
AM, Rubin RJ (1997) Extracorporeal membrane oxygenation exposes infants
to the plasticizer, di(2-ethylhexyl)phthalate. Crit Care Med,
25(4):696-703.

Kicheva YI, Kostov VD, Chichovska M (1995) In vitro and in vivo studies
of the effect of the concentration of plasticizer di(2-ethylhexyl)
phthalate on the blood compatibility of plasticized poly(vinyl chloride)
drain tubes. Biomaterials 16(7):575-9.

Kim SW, Petersen RV, and Lee ES (1976) Effect of phthalate plasticizer
on blood compatibility of polyvinyl chloride. J Pharm Sci. 65(5):670-3.

Lamba NM, Courtney JM, Gaylor JD, and Lowe GD (2000) *In vitro*
investigation of the blood response to medical grade PVC and the effect
of heparin on the blood response. Biomaterials 21(1):89-96.

Lee JH, Kim KO, and Ju YM (1999) Polyethylene oxide additive-entrapped
polyvinyl chloride as a new blood bag material. J Biomed Mater Res.
48(3):328-34.

Nassberger L and Arbin A (1987) Eosinophilic peritonitis\--hypothesis.
Nephron 46(1):103-4.

Solary E, Cabanne JF, Tanter Y, and Rifle G (1986) Evidence for a role
of plasticizers in \'eosinophilic\' peritonitis in continuous ambulatory
peritoneal dialysis. Nephron 42(4):341-2.

Stabellini G, Bedani PL, Fiocchi O, Calastrini C, Pagliarini A, Lunghi
M, Carinci F, Pellati A, Giuliani A, and Berti G (1998) DEHP-induced
alterations in the lining tissue of the rat air pouch. Int J Artif
Organs 21(2):87-94.

Taylor RL, Borger MA, Weisel RD, Fedorko L, and Feindel CM (1999)
Cerebral microemboli during cardiopulmonary bypass: increased emboli
during perfusionist interventions. Ann Thorac Surg. 68(1):89-93.

Webb JS, Van der Mei HC, Nixon M, Eastwood IM, Greenhalgh M, Read SJ,
Robson GD, and Handley PS (1999) Plasticizers increase adhesion of the
deteriogenic fungus Aureobasidium pullulans to polyvinyl chloride. Appl
Environ Microbiol. 65(8):3575-81.

Wendel HP and Ziemer G. (1999) Coating-techniques to improve the
hemocompatibility of artificial devices used for extracorporeal
circulation. Eur J Cardiothorac Surg. 16(3):342-50.

Yano R, Nakamura T, Aono H, Wakiya Y, Masada M. (2001) The amount of the
loss of cyclosporine A dose correlated with the amount of leaching di
(2-ethylhexyl) phthalate from polyvinyl chloride infusion tube. Yakugaku
Zasshi 121(2):139-44 (Japanese).

Yianni JP (1995) Making PVC more biocompatible. Med Device Technol.
6(7):20-6, 28-9.

Zhao X and Courtney JM (1999) Influence on blood of plasticized
polyvinyl chloride: significance of the plasticizer. Artif Organs
23(1):104-7.