Document ID: EPA-HQ-OPPT-2002-0009-0009
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2003-07-03T04:00Z

I
4'
­

Dibasic
Esters
:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
Laboratory
Project
ID:
DuPont­
5295
TESTGUIDELINES:
OECD
Guideline
for
the
Testing
of
Chemicals
(
Draft
Guideline
428),
Skin
Absorption:
in
vitro
Method
(
20015)

AUTHOR:
William
J.
Fasano,
Sr.,
B.
S.

STUDYCOMPLETEDON:
March
24,2003
SPONSOR:
Dibasic
Esters
Group
1100
New
York
Avenue,
N.
W.,
Suite
1090
Washington,
D.
C.
20005
PERFORMINGLABORATORY:
E.
I.
du
Pont
de
Nemours
and
Company
Haskell
Laboratory
for
Health
and
Environmental
Sciences
Elkton
Road,
P.
O.
Box
50
Newark,
Delaware
19714­
0050
WORKREQUESTNUMBER:
13395
SERVICE
CODENUMBER:
1377
Page
1
of41
OPPT­
2002­
0009­
0009
Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
GOOD
LABORATORY
PRACTICE
COMPLIANCE
STATEMENT
This
study
was
conducted
in
compliance
with
U.
S.
EPA
TSCA
(
40CFR
part
792)
Good
Laboratory
Practice
Standards
except
for
the
item
documented
below.
The
item
listed
does
not
impact
the
validity
of
the
study.

The
test
substances
were
characterized
by
the
sponsor
prior
to
the
initiation
of
this
study.
AIthough
the
characterizations
were
not
performed
under
Good
Laboratory
Practice
Standards,
the
accuracy
of
the
data
is
considered
sufficient
for
the
purposes
of
this
study.

Study
Director:
2q­
MA­
SL­
2003
Willw
J.
Eano,
Sr.,
B.
S.
Date
Research
Toxicologist
n
Dibasic
Esters:
In
Vitro
Dermal
Permeability
 
i
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
QUALITY
ASSURANCE
STATEMENT
Haskell
Sample
Number(
s):

24296,25333,24300,24301
Dates
of
Inspections:

Protocol:
August
30,2002
Conduct:
August
30,2002;
November
1,2002
Records,
Reports:
January
27,28,30,31,2003;
February
3,4,2003
Dates
Findings
Reported
to:

Study
Director:
November
1,2002;
February
4,2003
Management:
November
1,2002;
February
24,2003
Reported
by:
c
2qtf.
fkl.
2~~
3
Joseph
C.
Hamill
Date
Staff
Quality
Assurance
Auditor
­
3­
Director:
r 

Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
CERTIFICATION
We,
the
undersigned,
declare
that
this
report
provides
an
accurateevaluation
of
data
obtained
from
this
study.

Approved
by:
Zcf­
Misk­
Lou3
Gary
W.
Jepson,
Ph.
D.
Date
Principal
Research
Toxicologist
and
Manager
Approved
by:

Issued
by
Study
Matthew
S.
BogdanfG,
Ph.
D.#
A@
V..
Research
Manager
and
Director
L5­
d
Willia
.
Fasano,
Sr.,
B.
S.
ResGrch
Toxicologist
­
42q
M~
zd0.3
Date
29­
frlA+­
2003
Date
Dibasic
Esters:
In
Vitro
Dermal
Permeability
.
Coefficients(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
TABLE
OF
CONTENTS
Page
GOOD
LABORATORY
PRACTICE
COMPLIANCE
STATEMENT
..................................
2
QUALITY
ASSURANCE
STATEMENT...................................................................................
3
CERTIFICATION
........................................................................................................................
4
LIST
OF
TABLES
........................................................................................................................
7
LIST
OF
FIGURES
......................................................................................................................
7
LIST
OF
APPENDICES...............................................................................................................
7
STUDY
INFORMATION.............................................................................................................
8
STUDY
PERSONNEL................................................................................................................
11
SUMMARY..................................................................................................................................
12
INTRODUCTION
.......................................................................................................................
14
MATERIALS
AND
METHODS
...............................................................................................
14
A.
Regulatory
Test
Guidelines
...............................................................................................
14
B
.
Test
Substances.................................................................................................................
15
C.
Analytical
Reference
Standard..........................................................................................
15
D.
Test
System
.......................................................................................................................
16
1.
Rat
Skin
.......................................................................................................................
16
2.
Human
Skin.................................................................................................................
17
E.
Test
Solution
Information
.................................................................................................
17
1.
Formulation
.................................................................................................................
17
2.
Administration
and
Concentration
..............................................................................
17
F.
Exposure
Groups
...............................................................................................................
17
G.
Preparation
of
Skin
Membranes
........................................................................................
17
1
.
Rat
Skin
.......................................................................................................................
17
2.
Human
Skin.................................................................................................................
18
H.
In
VitroFlow­
Through
Diffusion
Cells
............................................................................
18
I.
Assessment
of
Membrane
Integrity
and
Membrane
Equilibration....................................
18
J
.
In
Vitro
Percutaneous
Penetration
.....................................................................................
19
K.
Sample
Analysis
................................................................................................................
19
L.
Data
Evaluation
.................................................................................................................
20
M.
Statistical
Analyses............................................................................................................
20
­
5­
Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
RESULTS
AND
DISCUSSION
.................................................................................................
21
A.
Permeability
parameters
for
individual
DBE
homologues................................................
21
B.
Permeability
parameters
for
the
DBE
homologues
in
the
1:
3:
1
(
DMS:
DMG:
DMA)
blend.................................................................................................
21.
C.
Comparison
of
permeability
coefficient
(
Kp)
data
within
a
species
.................................
22
CONCLUSIONS.........................................................................................................................
22
RECORDS
AND
SAMPLE
STORAGE
...................................................................................
23
REFERENCES............................................................................................................................
23
TABLES.......................................................................................................................................
24
FIGURES
.....................................................................................................................................
28
APPENDICES
.............................................................................................................................
34
­
6­
,
Dibasic
Esters:
In
Vitro
Dermal
Permeability
,
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
LIST
OF
TABLES
Page
1.
Permeability
parameters
for
individual
DBE
homologues......................................................
26
2.
Permeability
parameters
for
DBE
homologues
in
the
1:
3:
1blend
(
DMS:
DMG:
DMA).........
27
LIST
OF
FIGURES
Page
1.
Individual
DBE
homologues­
comparison
of
permeability
coefficients
(
Kp)
for
rat
and
human
skin........................................................................................................................
30
2.
DBE
1:
3:
1
@
MS:
DMG:
DMA)
blend
­
comparison
of
permeability
coefficients
(
Kp)
for
rat
and
human
skin.............................................................................................................
31
3.
A
comparison
of
permeability
coefficients.(
Kp)
for
the
individual
DBE
homologues
and
the
homologues
in
the
1:
3:
1
@
MS:
DMG:
DMA)
blend
for
rat
skin
................................
32
4.
A
comparison
of
permeability
coefficients
(
Kp)
for
the
individual
DBE
homologues
and
the
homologues
in
the
1:
3:
1
(
DMS:
DMG:
DMA)
blend
for
human
skin
.........................
33
LIST
OF
APPENDICES
Page
A.
Permeability
parameters
for
the
individual
DBE
homologues
­
individual
data
for
DMS,
DMG,
and
DMA
when
applied
to
rat
and
human
skin.................................................
36
B.
Permeability
parameters
for
the
individual
DBE
homologues
in
the
1:
3:
1
(
DMS:
DMG:
DMA)
blend
­
individual
data
for
DMS,
DMG,
and
DMA
when
applied
to
rat
and
human
skin
..............................................................................................................
39
­
7
­
Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
STUDY
INFORMATION
Test
Substance
1:

9th
CollectiveNomenclature:
Butanedioic
acid,
dimethyl
ester
SynonvmsKodes:
Dimethyl
succinate
DBE­
4
DMS
F124347A
(
Lot
No.)

Haskell
Number:
25333
CAS
Registry
Number:
106­
65­
0
DuPont­
5295
Composition:
99.2%
Dimethyl
succinate
@
MS­
DBE4)

Known
Impurities:
0.2
wt%
Dimethyl
glutarate
(
DMG­
DBE5)
0.03
wt%
Water
Phvsical
Characteristics:
Colorless
liquid
Test
Substance
2:

9th
Collective
Nomenclature:
Pentanedioicacid,
dimethy1ester
SvnonvmsKodes:
Dimethyl
glutarate
DBE­
5
DMG
0
Dimethyl
Glutarate
(
DMG)
H931363­
A
(
Lot
NO.)

Haskell
Number:
24300
CAS
Repistry
Number:
1119­
40­
0
Composition:
99.61%
Dimethyl
glutarate
(
DMG­
DBE5)
by
gas
chromatography
(
GC)

Known
Impurities:
0.085%
Dimethyl
adipate
@
MA­
DBEG)
by
GC
0.163%
Dimethyl
succinate
OMS­
DBE4)
by
GC
2.8ppm
HCN
Physical
Characteristics:
Colorless
liquid
r).
Dibasic
Esters:
In
VitroDermal
Permeability
,
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
Test
Substance
3:

9th
Collective
Nomenclature:
Hexanedioic
acid,
dimethyl
ester
SvnonvmdCodes:

0
e
e
e
0
e
0
Dimethyl
adipate
DBE­
6
DMA
Adipic
acid,
dimethyl
ester
Dimethyl
hexanedioate
Methyl
adipate
Dibasic
ester­
6
J806339­
A
(
Lot
NO.)

Haskell
Number:
24301
CAS
Registry
Number:
627­
93­
0
Composition:
98.824%

Known
Imuurities:
0.607%
4.8ppm
Dimethyl
adipate
@
MA­
DBE6)
by
GC
Dimethyl
glutarate
(
DMG­
DBE5)
by
GC
HCN
Physical
Characteristics:
Colorless
Iiquid
Test
Substance
4:

Substance
Tested:
DBE
Synonyms/
Codes:
0
Aliphatic
dibasic
esters
­
DBE
Dibasic
ester
Dibasic
ester
mixture
0
18077336
(
Lot
NO.)

Haskell
Number:
24296
CAS
Registry
Number:
1119­
40­
0
Dimethyl
glutarate
627­
93­
0
Dimethyl
adipate
106­
65­
0
Dimethyl
succinate
Composition:
58.92%
Dimethyl
glutarate
(
DMG­
DBES)
by
GC
2
1.92%
Dimethyl
adipate
(
DMA­
DBE6)
by
GC
18.76%
Dimethyl
succinate
(
DMS­
DBE4)
by
GC
­
9­
Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
Known
Impurities:
0.09%
MEOH
4.8ppm
HCN
Phvsical
Characteristics:
Colorless
liquid
Sponsor:
Dibasic
Esters
Group
1100
New
York
Avenue,
N.
W.,
Suite
1090
Washington,
DC
20005
Study
InitiatedCompleted:
July
26,2002
/
(
see
report
cover
page)

­
10­
_
I
I
,

Dibasic
Esters:
In
Vitro
Dermal
Permeability
,
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
STUDY
PERSONIWL
Study
Director:
William
J.
Fasano,
Sr.,
B.
S.
Management:
Matthew
S.
Bogdanffy,
Ph.
D.,
D.
A.
B.
T.
Gary
W.
Jepson,
Ph.
D.
Primary
Technician:
LaRue
A.
Manning,
B.
A.
Analytical
Associate:
Julia
N.
Wang,
Ph.
D.

Toxicology
Report
Preparation:
Lisa
G.
Burchfield,
A.
A.
Management:
Nancy
S.
Selzer,
M.
S.

Laboratory
Veterinarian:
Thomas
W.
Mayer,
D.
V.
M.,
A.
C.
L.
A.
M.
William
Singleton,
D.
V.
M.,
A.
C.
L.
A.
M.

­
11
­
Dibasic
Esters:
In
Vim
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
HumanSkin
DuPont­
5295
SUMMARY
The
in
vitro
dermal
kinetic
parameters
of
penetration
rate,
lag
time,
and
permeabilitycoefficient
(
Kp)
were
determined
for
rat
and
human
skin
for
the
refined
individual
Dibasic
Ester
@
BE)
homologuesDimethyl
Succinate(
DMS),
Dimethyl
Glutarate
(
DMG),
and
Dimethyl
Adipate
(
DMA),
and
for
the
homologues
in
a
1:
3:
1
(
DMS:
DMG:
DMA)
blend.
Split­
thicknessrat
skin
and
human
epidermal
membranes
were
mounted
in
a
flow­
through
diffusion
cell
system
which
was
maintained
at
32
°
C.
Skin
specimens
were
equilibrated
with
a
0.9%
saline
receptor
fluid
and
integrityconfirmed
by
electricalresistance.
Following
specimen
selection
and
replacement
of
the
saline
receptor
fluid
with
1:
1
(
v/
v)
ethano1:
water
maintained
at
a
flow
rate
of
approximately
2
mUh,
an
infinite
dose
(
150
pL)
of
the
test
solvent
was
applied
to
the
epidermal
surface
of
6
skin
replicatesper
species.
Under
occlusive
conditions,
receptor
chambereffluent
samples
were
collected
hourly
for
each
replicate
until
6
hours
post­
application.
Quantitative
analysis
of
receptor
fluid
samples
for
the
DBE
homologue
of
interest
was
performed
using
a
liquid
chromatograph
coupled
to
a
mass
spectrometeroperating
in
multiple
reaction
mode.

Following
application
of
the
individual
dibasic
ester
homologues
DMS,
DMG,
and
DMA
to
rat
and
human
skin,
the
penetration
rates
for
each
homologue
were
comparable
within
a
species
and
ranged
from
3131.8
to
4542.4
pg/
cm2/
hfor
rat
skin
and
from
79.5
to
113.0
pg/
cm2/
hfor
human
skin.
In
contrast,
when
the
DBE
blend
containingDMS,
DMG,
and
DMA
in
a
nominal
ratio
of
1:
3:
1
(
v/
v)
was
applied
to
rat
skin,
the
penetration
rate
for
DMS
(
571.7
pg/
cm2/
h),
DMG
(
1571
pg/
cm2/
h),
and
DMA
(
507.0
pg/
cm2/
h)
was
slower
compared
to
the
penetration
rates
observed
when
the
individual
homologues
were
applied
alone
as
a
single
solvent
system.
The
rate
of
DMG
Penetration
from
the
blend
was
approximately3­
fold
fastercompared
to
DMS
and
DMA,
owing
to
its
concentration
as
penetration
is
passive
and
concentration
dependent.

As
was
observed
for
rat
skin,
the
penetration
rate
for
DMG
through
human
skin
from
the
homologue
blend
(
108.7
pg/
cm2/
h)
was
faster
compared
to
DMS
(
24.2
pg/
cm2/
h)
and
DMA
(
16.3
pg/
cm*/
h).
With
the
exception
of
DMG,
the
penetration
rates
for
DMS
and
DMA
were
slower
as
measured
from
the
blended
solvent
system
compared
to
the
penetration
rates
observed
when
each
homologue
was
applied
alone
to
human
skin.

Overall,
and
exclusive
of
whether
the
DBE
homologue
was
applied
alone
or
as
part
of
the
blended
formulation,
lag
times,
a
measure
of
the
time
required
for
the
DBE
homologue
to
cross
the
skin
and
appear
in
the
receptor
fluid,
were
shorter
for
rat
skin
(
20.15
hours)
than
for
human
skin
(
10.64
hours).

The
permeability
coefficients(
Kp),
whether
the
DBE
homologue
was
applied
alone
or
as
part
of
the
1:
3:
1
blend,
were
comparablefor
each
homologue
within
a
species
and
higher
for
rat
skin
compared
to
human
skin.
The
Kp
values
for
rat
and
human
skin
ranged
from
2.12
x
to
4.18
x
lo"
cdh
and
from
6.81
x
to
1.69
x
respectively.

The
results
from
these
in
vitro
dermal
kinetic
experiments
show
that
DMS,
DMG,
and
DMA
penetrated
through
rat
skin
faster
and
with
a
shorter
lag
time
than
was
observed
for
human
skin.

­
12­
Dibasic
Esters:
In
VitroDermal
Permeability
.
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
The
data
also
show
that
the
permeability
coefficient
was
comparable
for
each
dibasic
ester
homologue
within
a
species
and
exclusiveof
whether
the
DBE
of
interest
was
applied
alone
as
a
single
solvent
system
or
as
part
of
the
1:
3:
1
(
DMS:
DMG:
DMA)
blend.

The
permeability
coefficient,
which
serves
to
describe
the
movement
or
flux
of
a
chemical
through
skin
and
principally
the
stratum
corneum,
normalized
for
concentrationand
expressed
as
a
depth
of
diffusion
per
unit
of
time,
provides
a
basis
for
comparisonwith
other
industrial
solvents
and
is
useful
in
estimating
absorbed
dose
following
dermal
exposure.

­
13­
Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
INTRODUCTION
Dibasic
Esters
(
DBEs)
are
used
in
degreasing
and
paint
stripping
operations
and
as
a
replacement
for
traditional
aromatic
solvents.
The
DBEs
are
identified
as
Dimethyl
Succinate
(
DMS),
Dimethyl
Glutarate
(
DMG),
and
Dimethyl
Adipate
@
MA).
Based
on
the
potential
for
dermal
exposure
to
DBEs,
comparative
in
vitro
dermal
kinetic
data
in
rat
and
human
skin
was
requested
by
the
sponsor
in
order
to
comply
with
an
EPA­
issued
consent
order
pursuant
to
TSCA
section
4.

This
study
was
designed
to
determine
a
permeability
coefficient
(
Kp)
for
each
DBE
homologue
alone,
and
for
each
homologue
in
a
1:
3:
1
v/
v
blended
formulation
of
DMS:
DMG:
DMA.
The
data
generated
in
this
study
can
be
used
in
evaluating
dermal
exposure
to
DBEs.

A
permeability
coefficient
(
Kp),
which
is
a
conservative
measure
of
penetration
since
it
is
determined
with
an
infinite
application
of
the
solvent
and
under
steady­
state
penetration,
is
useful
for
predicting
absorbed
dose
in
vivo
using
the
following
equation:

Q
=
Kp
*
A
*
C
*
(
T­
Z)

Where
Q
is
the
amount
of
the
homologue
absorbed
(
mg),
Kp
is
the
permeability
coefficient
(
crdh),
A
is
the
skin
exposure
area
(
cm2),
C
is
the
concentration
of
the
homologue
in
the
solution,
whether
applied
alone
or
in
the
1:
3:
1
(
DMS:
DMG:
DMA)
v/
v
blend
(
mg/
mL),
Tis
the
exposure
time
(
hours),
and
Tis
the
lag
time,
or
time
required
for
the
solvent
to
cross
the
skin
barrier
and
reach
the
systemic
circulation.'')

Kp
values
are
primarily
a
function
of
the
octanol­
water
partition
coefficient,
molecular
weight,
molecular
volume,
and
thickness
of
the
stratum
corneum.
Considered
the
rate­
limiting
barrier
to
penetration,
the
sfraturncumeurn
is
the
outermost
layer
of
skin
and
is
composed
of
vertically­
stacked,
polyhedral
comeocytes
surrounded
by
a
matrix
of
lipid­
enriched
membranes.'*)

In
addition
to
performing
exposure
assessments
for
the
individual
DBE
homologues
alone
and
in
the
blend,
Kp
values
are
useful
for
making
comparisons
to
existing
Kp
data
for
various
industrial
solvents.

MATERIALS
AND
METHODS
A.
Regulatory
Test
Guidelines
This
study
was
not
designed
to
meet
any
specific
regulatory
guideline
requirement.
However,
there
are
guidelines
on
percutaneous
absorption
from
the
Organization
for
Economic
Co­
operation
and
Development
(
OECD),
which
provides
information
on
the
practical
use
of
the
in
vitro
dermal
absorption
meth~
d.'~'

­
14­
Dibasic
Esters:
In
Vitro
Dermal
Permeability
.
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
B.
Test
Substances
The
test
substances,
DMS,
DMG,
DMA,
and
a
1:
3:
1
(
v/
v)
blend
of
DMS:
DMG:
DMA
were
supplied
by
the
sponsor
and
assigned
unique
Haskell
Laboratory
Numbers
upon
receipt.
Available
information
on
the
purity,
composition,
contaminants,
synonyms,
basic
physical
properties,
hazards,
and
hazardous
material
classification(
s)
was
provided
by
the
sponsor
and
documented
in
the
study
records.
The
samples
were
stored
at
room
temperature.

General
Information
and
Structures
Dimethyl
succinate
@
MS)
0
Molecular
Weight:
146
0­
II
CASRN:
106­
65­
0
 
I1
0 

Haskell#
25333
0
Dimethyl
glutarate
(
DMG)
Molecular
Weight:
160
O\
CASRN:
1119­
40­
0
0
0
HaskeIl#
24300
Dimethyl
adipate
(
DMA)
0
Molecular
Weight:
174
CASRN:
627­
93­
0
1,

Haskell#
24301
0
The
1:
3:
1
(
v/
v)
blend
of
DMS:
DMG:
DMA
was
assigned
Haskell#
24296.

Dibasic
esters
are
clear
liquids
at
room
temperature,
with
high
boiling
points,
low
vapor
pressures,
and
low
solubility
in
water,
but
are
generally
soluble
in
alcohols.

C.
Analytical
Reference
Standard
Reference
standards
of
DMS,
DMG,
and
DMA
were
purchased
from
Sigma­
Aldrich
Corporation
(
St.
Louis,
MO)
and
had
a
chemical
purity
of
98%.
The
standards
were
assigned
Haskell
Laboratory
Numbers
22703­
239
(
DMS),
22703­
240
(
DMG),
and
22703­
241
(
DMA)
and
were
stored
at
room
temperature.
The
reference
standards
served
to
confirm
the
identity
of
each
DBE
in
the
test
substances
and
the
concentration
of
DBEs
in
receptor
fluid
samples.
Dibasic
Esters:
In
Vitro
Dermal
Permeability
CoeMicients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
D.
Test
System
1.
RatSkin
Skin
used
was
from
male
rats
of
the
Sprague­
Dawleystrain,
Crl:
CD@(
SD)
IGSBR,
6­
8
weeks
of
age.
Rats
were
supplied
by
Charles
River
Laboratories,
Inc.,
Raleigh,
North
Carolina.

Animal
Husbandry
Upon
arrival
at
Haskell
Laboratory,
animals
were
removed
from
shipping
cartons
and
housed
in
appropriate
cages,
according
to
Standard
Operating
ProceduresLAOO3­
P
unless
specified
in
the
study
records.
Animals
were
maintained
under
quarantine
for
at
least
6
days
unless
approved
otherwise
by
the
site
veterinarian,
had
3
recorded
weight
gains
and
no
abnormalities
detected.
After
the
quarantine
period,
rats
were
selected
for
study.

Animal
rooms
are
targeted
at
a
temperatureof
23
21
°
C
and
a
relative
humidity
of
40­
60%.
Animal
rooms
are
artificially
illuminated
(
fluorescent
light)
on
an
approximate
12­
hour
lighvdark
cycle.

All
animals
were
provided
tap
water
ad
libitum
and
fed
PMI
Nutrition
International,
Inc.
Certified
Rodent
LabDiet@
5002
ad
libitum
during
the
quarantine
period.

Animal
Health
Monitoring
As
specified
in
the
Haskell
Laboratory
animal
health
and
environmental
monitoring
program,
the
following
procedures
are
performed
periodically
to
ensure
that
contaminant
levels
are
below
those
that
would
be
expected
to
impact
the
scientific
integrity
of
the
study:

Water
samples
are
analyzed
for
total
bacterial
counts,
and
the
presence
of
coliforms,
lead,
and
other
contaminants.

Feed
samples
are
analyzed
for
total
bacterial,
spore,
and
fungal
counts.

Samples
from
freshly
washed
cages
and
cage
racks
are
analyzed
to
ensure
adequate
sanitation
by
the
cagewashers.

Certified
animal
feed
is
used,
guaranteed
by
the
manufacturerto
meet
specifiednutritional
requirements
and
not
to
exceed
stated
maximum
concentrationsof
key
contaminants,
including
specified
heavy
metals,
aflatoxin,
chlorinated
hydrocarbons,
and
organophosphates.
The
presence
of
these
contaminants
below
the
maximum
concentration
stated
by
the
manufacturer
would
not
be
expected
to
impact
the
integrity
of
the
study,

The
animal
health
and
environmental
monitoring
program
is
administeredby
the
attending
laboratoryanimal
veterinarian.
Evaluation
of
these
data
did
not
indicate
any
conditions
that
affected
the
validity
of
the
study.

­
16­
Dibasic
Esters:
In
Vitro
Dermal
Permeability
.
Coefficients(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
2.
Human
Skin
Samples
of
human
skin
(
lateral
thigh),
harvested
postmortem,
was
supplied
by
the
International
Institute
for
the
Advancement
of
Medicine
(
Jessup,
PA).
The
skin
samples
were
stored
frozen
at
approximately
­
20
°
C
until
prepared
for
use.
The
source
and
identity
of
the
skin
samples
(
sex
and
approximate
age
of
donor)
were
documented
in
the
study
records.

E.
Test
Solution
Information
1.
Formulation
The
test
substances
were
applied
as
received.

2.
Administration
and
Concentration
The
test
substances
were
applied
to
each
test
skin
as
a
single,
infinite
dose
of
150
pL.

The
concentration
of
each
individual
homologue
alone
and
in
the
blend
@
g/
mL)
wasbased
on
data
supplied
by
the
sponsor.

F.
Exposure
Groups
The
following
exposure
groups
were
used
to
determine
the
in
vitro
dermal
permeability
coefficients
(
Kp)
in
rat
and
human
skin,
when
applied
either
as
a
pure
solvent,
or
when
incorporated
into
a
blended
formulation.

Species
Test
Group
DBE
Test
Solution
Number
of
Skin
Preparations
Rat
A
B
C
D
Human
E
F
G
H
DMS
DMG
DMA
1:
3:
1
(
DMS:
DMG:
DMA)
blend
DMS
DMG
DMA
1:
3:
1
(
DMS:
DMG:
DMA)
blend
6
6
6
6
G.
Preparationof
Skin
Membranes
1.
RatSkin
Following
quarantine,
rats
were
euthanized
by
carbon
dioxide
asphyxiation
and
the
fur
from
the
dorsal
region
was
carefully
shaved
using
clippers.
Any
animals
showing
obvious
abrasion
within
the
region
of
the
test
skin
area
were
considered
unsuitable
and
discarded.
The
shaved
area
was
excised,
held
briefly
on
wet
ice,
and
frozen
at
approximately
­
20
°
Cuntil
processed.

­
17­

I
Dibasic
Esters:
In
VitroDermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
Samples
of
skin
were
removed
from
storage,
thawed
at
room
temperature,
then
dermatomed
to
approximately
450
pm.
The
skin
sample
was
then
placed
onto
an
aluminum
pan,
identified
using
the
Haskell
animal
number,
and
stored
refrigerated
at
approximately0­
10
°
C
until
readied
for
use.

2.
Human
Skin
Samples
of
human
skin,
which
were
stored
frozen,
were
allowed
to
thaw
at
room
temperature,
and
any
extraneous
tissue
was
removed
(
e.
g.,
subcutaneousfat).
The
skin
section
was
then
immersed
in
approximately60
°
C
water
for
approximately50
seconds,
removed,
and
the
epidermis
peeled
off
the
dermis.
Each
membrane
was
floated
onto
an
aluminum
pan
and
the
excess
water
allowed
to
drain
away.
Each
membrane
was
given
a
unique
identifying
number
and
stored
refrigerated
at
approximately0­
10
°
C
until
readied
for
use.

H.
In
Vitro
Flow­
Through
Diffusion
Cells
An
automated
flow­
throughdiffusion
cell
system
(
PermeGear,
Inc.,
Bethlehem,
PA)
was
used
in
this
study.
The
skin
membrane
was
mounted,
dermal­
side
down,
onto
the
top
of
the
receptor
chamber.
The
donor
chamber
(
top)
was
then
placed
over
the
skin
section,
clamped
in
place,
and
fluid
pumped
under
the
skin
section.
The
in
vitro
cells
have
an
exposure
area
of
0.64
cm2.

I.
Assessment
of
Membrane
Integrity
and
Membrane
Equilibration
The
integrity
of
each
membrane
was
assessed
by
measurement
of
electrical
resistanceprior
to
application
of
test
substance.")

Membranes
were
removed
from
refrigeration
storage
and
hydrated
in
0.9%
saline.
Following
hydration,
the
membrane
was
mounted
onto
the
top
of
the
receptor
chamber
and
the
donor
chamber
clamped
in
place.
Physiologic
saline
(
0.9%)
was
then
pumped
through
the
system
at
a
rate
of
approximately
2
mUh,
and
the
membrane
equilibrated
in
the
test
system
for
approximately
30
minutes.
During
equilibration,
the
water­
jacketed
cells
were
maintained
at
approximately
32OC
using
a
recirculating
water
bath
system.
Followingequilibration,
a
resistance
measurement
of
each
skin
membrane
was
taken
using
a
Tinsley
6401
Databridge
(
H.
Tinsley
and
Company,
Croydon,
Surrey,
England).

Membranes
with
a
resistance
of
26
kS2
(
rat)
and
217
kSZ
(
human)
were
considered
intact
and
retained
for
use
on
study.
Membranes
not
meeting
these
criteria
were
replaced,
and
electrical
resistance
confirmed
followingequilibration.
This
procedure
was
followed
until
a
minimum
of
6
skin
preparationsrepresented
by
at
least
2
individuals
per
species
per
formulation
was
achieved.

Following
electrical
resistance
measurement,
the
saline
in
the
donor
chamber
was
removed
and
discarded.
The
rate
of
flow
of
saline
through
the
receptor
chamber
was
maintained
at
approximately
2
Wh,
and
the
in
vitro
cells
held
overnight
without
occlusion
of
the
donor
chamber,
prior
to
test
solution
application.

­

18ri
Dibasic
Esters:
In
Vim
Dermal
Permeability
*
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
J.
In
Vitro
Percutaneous
Penetration
Following
overnight
equilibration,
the
saline
receptor
fluid
was
discarded
and
replaced
with
1:
1
ethano1:
water
(
vh)
and
the
flow
rate
increased
for
a
period
of
time
sufficient
to
purge
the
system
of
saline.
Following
this,
the
flow
rate
was
adjusted
to
approximately2
mUhand
the
system
equilibrated
for
approximatelyone
hour
prior
to
application
of
the
test
solution.

The
test
solution
(
150
pL)
was
then
applied
to
the
skin
surface,
via
the
donor
chamber,
and
the
donor
chamber
occluded
with
tape
for
the
duration
of
the
exposure
period.

Following
dose
application,
samples
of
receptor
fluid
were
collected
at
1,2,3,4,5,
and
6
hours
for
all
skin
preparations.
Samples
not
immediatelyprocessed
for
analysis
were
stored
frozen
at
5­
10
°
C.

K.
Sample
Analysis
Quantitativeanalysis
of
receptor
fluid
samples,
along
with
reference
standards,
was
performed
using
a
Waters
Alliance@
2790
Liquid
Chromatograph(
LC)
coupled
to
a
Micromass
Quattro
microTM
tandem
quadrapole
mass
spectrometer(
MS)
equipped
with
a
MASSLYNX
data
acquisition
system
(
Micromass
Inc.,
Manchester,
UK).

LC
Conditions:
Column:
HP
Zorbax
RxC8,2.1
x
150
mm.
5pm
particles
Column
temperature:
20
°
C
Injection
volume:
5
PL
Solvent
A
10mM
formic
acid
in
water
Solvent
B:
Acetonitrile
Gradient:
Time
A
B
0
80
20
5.00
30
70
6.00
30
70
6.10
80
20
Flow
rate:
0.450mUmin
MS
Conditions:
Ionization
mode:
Electrospray
positive
(
ES+)
Capiilary
voltage:
3.20
kV
Cone
voltage
25.8
V
Extractor
voltage:
4.20
V
Source
temperature:
100
°
C
Cone
temperature:
20
°
C
Desolvation
temperature:
250
°
C
Cone
gas
flow:
84L/
Hr
(
nitrogen)
Desolvation
gas
flow:
668UHr
(
nitrogen)
Collision
energy:
4eV
Collision
gas:
Argon
Mode:
Multiple
Reaction
Monitoring(
MRM)
(
a)
147.07>
114.93for
DMS
(
b)
161.05
>
128.92for
DMG
(
c)
175.07>
142.94for
DMA
­
19­
Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
L.
Data
Evaluation
The
cumulative
amount
of
test
material
penetrating
the
membrane
and
appearing
in
the
receptor
fluid
at
each
sampling
time­
point,
divided
by
the
exposure
area
(
0.64
cm2)
was
plotted
versus
time
(
hours)
on
a
linear
scale.
The
linear
portion
of
this
plot,
containing
a
minimum
of
three
data
points,
represents
steady­
state
penetration.
The
slope
of
this
portion
of
the
line
was
the
test
material
flux
(
e.
g.,
pg/
cm%).

Lag
time,
a
measure
of
the
amount
of
time
required
for
a
chemical
to
penetrate
through
the
skin
membrane
and
enter
the
receptor
fluid,
was
determined
by
back­
extrapolation
of
the
steady­
state
penetration
line
with
the
x­
axis.

The
permeability
coefficient
(
Kp)
was
calculated
by
dividing
the
flux
at
steady­
statepenetration
(
e.
g.,
pg/
crn2/
h)
by
the
concentration
of
the
applied
dose
(
e.
g.,
pg/
cm3).

M.
Statistical
Analyses
Group
data
was
represented
at
Mean
.
c
SD.
The
statistical
significance
of
the
Kp
results
was
assessed
by
the
Student s
T­
test
using
Microcalm
OriginTM,
version
7.0
(
OriginLab
Corporation,
Northampton,
MA).
A
p­
value
of
50.05
was
considered
significant.

­
20­

I
Dibasic
Esters:
In
Vitro
Dermal
Permeability
.
CoeEcients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
RESULTS
AND
DISCUSSION
A.
Permeability
parameters
for
individual
DBE
homologues
(
Table
1,
Figure
1)

Key
observations
of
mean
data:

Following
application
of
the
individual
DBE
homologues
(
DMS,
DMG,
and
DMA),
the
penetration
rates
for
each
homologue
were
comparable
within
a
species
and
ranged
from
3131.8
to
4542.4
pg/
cm2/
hfor
rat
skin
and
from
79.5
to
113.0
pg/
cm2/
hfor
human
skin.

At
steady­
state,
the
penetration
rates
were
noted
to
be
faster
through
rat
skin
compared
to
human
skin
for
each
individual
DBE
homologue.

Lag
times,
a
measure
of
the
amount
time
required
for
the
DBE
homologue
to
cross
the
skin,
were
~
0.0
1
hours
and
0.26­
0.64
hours
for
rat
and
human
skin,
respectively.

Permeability
coefficient
(
Kp)
values
(
penetration
rate
data
normalized
for
the
applied
concentration
of
the
DBE
homologue)
for
rat
and
human
skin
ranged
from
2.98
x
to
4.18
x
lo 
cdh
and
from
7.56
x
lo­ 
to
1.02
x
respectively.
The
individual
DBE
homologues
penetrated
through
rat
skin
34.2­
to
43.9­
fold
faster
than
through
human
skin.

B.
Permeability
parameters
for
the
DBE
homologues
in
the
1:
3:
1
(
DMS:
DMG:
DMA)
blend
(
Table
2,
Figure
2)

Key
observationsof
mean
data:

Following
application
of
the
DBE
blend
to
rat
skin,
the
penetration
rate
for
DMG
(
1571.
O
pg/
cm2/
h)
was
approximately
3­
fold
faster
than
the
rate
observed
for
DMS
(
571.7
pg/
cm*/
h)
and
DMA
(
507.0
pg/
cm2/
h).

As
was
observed
for
rat
skin,
the
penetration
rate
for
DMG
through
human
skin
(
108.7
pg/
cm2/
h)
was
faster
compared
to
the
rate
observed
for
DMS
(
24.2
pg/
cm2/
h)
and
DMA
(
16.3
pg/
cmZ/
h).

At
steady­
state,
the
penetration
rates
for
each
DBE
homologue
from
the
1:
3:
1
blend
were
noted
to
be
faster
through
rat
skin
compared
to
human
skin.

The
rate
of
penetration
for
the
DBE
homologues
from
the
1:
3:
1
blend
were
slower
compared
to
rates
observed
following
application
of
the
individual
dibasic
ester
homologues
alone
(
with
the
exception
of
DMG
for
human
skin).

Lag
times,
a
measure
of
the
amount
time
required
for
the
DBE
homologue
to
cross
the
skin,
were
0.12
to
0.15
hours
and
0.09
to
0.28
hours
for
rat
and
human
skin,
respectively.
Diba6ic
Esters:
In
Vitro
Dermal
Permeability
 
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
Permeability
coefficient
(
Kp)
values
(
penetration
rate
data
normalized
for
the
applied
concentration
of
the
DBE
homologue)
for
rat
and
human
skin
ranged
from
2.12
x
to
2.79
x
cdh
and
from
6.81
x
lo­ 
to
1.69
x
lo4
cdh,
respectively.
The
DBE
homologues
penetrated
through
rat
skin
14.5­
to
31.1­
fold
faster
than
through
human
skin.

C.
Comparison
of
permeability
coefficient
(
Kp)
data
within
a
species
(
Figures
3­
4)

Whether
the
dibasic
ester
of
interest
was
applied
alone
as
a
single
solvent
system
or
as
part
of
the
1:
3:
1
@
MS:
DMG:
DMA)
blend,
the
permeability
coefficients
for
DMS,
DMG,
and
DMA
were
comparable
within
a
species
and
were
higher
for
rat
skin
compared
to
human
skin.

CONCLUSIONS
Following
application
of
the
individual
dibasic
ester
homologues
DMS,
DMG,
and
DMA
to
rat
and
human
skin,
the
penetration
rates
for
each
homologue
were
comparable
within
a
species
and
ranged
from
3131.8
to
4542.4
pg/
cm2/
hfor
rat
skin
and
from
79.5
to
113.0
pg/
cm*/
hfor
human
skin.
In
contrast,
when
the
DBE
blend
containing
DMS,
DMG,
and
DMA
in
a
nominal
ratio
of
1:
3:
1
(
v/
v)
was
applied
to
rat
skin,
the
penetration
rate
for
DMS
(
571.7
pg/
cm2/
h),
DMG
(
1571
pglcm lh),
and
DMA
(
507.0
pg/
cm*/
h)
was
slower
compared
to
the
penetration
rates
observed
when
the
individual
homologues
were
applied
alone
as
a
single
solvent
system.
The
rate
of
DMG
penetration
from
the
blend
was
approximately
3­
fold
faster
compared
to
DMS
and
DMA,
owing
to
its
concentration
as
penetration
is
passive
and
concentration
dependent.

As
was
observed
for
rat
skin,
the
penetration
rate
for
DMG
through
human
skin
from
the
homologue
blend
(
108.7
pg/
cm2/
h)
was
faster
compared
to
DMS
(
24.2
pg/
cm2/
h)
and
DMA
(
16.3
pg/
cm2/
h).
With
the
exception
of
DMG,
the
penetration
rates
for
DMS
and
DMA
were
slower
as
measured
from
the
blended
solvent
system
compared
to
the
penetration
rates
observed
when
each
homologue
was
applied
alone
to
human
skin.

Overall,
and
exclusive
of
whether
the
DBE
homologue
was
applied
alone
or
as
part
of
the
blended
formulation,
lag
times,
a
measure
of
the
time
required
for
the
DBE
homologue
to
cross
the
skin
and
appear
in
the
receptor
fluid,
were
shorter
for
rat
skin
(
SO.
15
hours)
than
for
human
skin
(
50.64
hours).

The
permeability
coefficients
(
Kp),
whether
the
DBE
homologue
was
applied
alone
or
as
part
of
the
1:
3:
1
blend,
were
comparable
for
each
homologue
within
a
species
and
higher
for
rat
skin
compared
to
human
skin.
The
Kp
values
for
rat
and
human
skin
ranged
from
2.12
x
to
4.18
x
lo3
cdh
and
from
6.81
x
to
1.69
x
respectively.

The
results
from
these
in
vitro
dermal
kinetic
experiments
show
that
DMS,
DMG,
and
DMA
penetrated
through
rat
skin
faster
and
with
a
shorter
lag
time
than
was
observed
for
human
skin.
The
data
also
show
that
the
permeability
coefficient
was
comparable
for
each
dibasic
ester
homologue
within
a
species
and
exclusive
of
whether
the
DBE
of
interest
was
applied
alone
as
a
single
solvent
system
or
as
part
of
the
1:
3:
1
(
DMS:
DMG:
DMA)
blend.

­
22
­
Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
The
permeability
coefficient,
which
serves
to
describe
the
movement
or
flux
of
a
chemical
through
skin
and
principally
the
stratum
corneunt,
normalized
for
concentration
and
expressed
as
a
depth
of
diffusion
per
unit
of
time,
provides
a
basis
for
comparison
with
other
industrial
solvents
and
is
useful
in
estimating
absorbed
dose
followingdermal
exposure.

RECORDS
AND
SAMPLE
STORAGE
All
data
and
records
for
analytical
characterizationsconducted
by
the
sponsor
will
be
archived
by
the
sponsor.
Laboratory­
specific
or
site­
specific
raw
data,
such
as
personnel
files
and
equipment
records
will
be
retained
by
the
facility
where
the
work
was
done.

A
sample
of
each
test
substance
will
be
collected
for
archive
purposes
and
retained
at
HaskelI
Laboratory,
Newark,
Delaware.
Specimens
(
if
applicable),
raw
data,
and
the
final
report
will
be
retained
at
Haskell
Laboratory,
Newark,
Delaware,
or
at
Iron
Mountain
Records
Management,
Wilmington,
Delaware.

REFERENCES
1.
Roberts
MS
and
Walters
KA
(
1998).
The
RelationshipBetween
Structure
and
Barrier
Function
of
Skin.
In:
Dermal
Absorption
and
Toxicity
Assessment,
Vol91,
Edited
by
MS
Roberts
and
KA
Walters,
pp
1­
42.
Marcel
Dekker,
Inc.,
New
York,
NY.

2.
Potts
RO
and
Guy
RH
(
1994).
Drug
Transport
Across
the
Skin
and
the
Attainment
of
Steady­
StateFlux.
Proceedings
of
the
International
Symposium
on
ControlledRelease
of
Bioactive
Materials
21,
162­
163.

3.
OECD
Guideline
for
the
Testing
of
Chemicals
(
Draft
Guideline
428),
Skin
Absorption:
in
vitro
Method
(
2002).

4.
Fasano
WJ,
Manning
LA,
and
Green
JW(
2002).
Rapid
Integrity
Assessmentof
Rat
and
Human
Epidermal
Membranes
for
In
Vitro
Dermal
Regulatory
Testing:
Correlation
of
Electrical
Resistance
with
Tritiated
Water
Permeability.
Toxicology
In
Vitro
16,731­
740.

­
23
­
Dibasic
Esters:
In
Vim
DermaI
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
TABLES
­
24­
Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
TABLES
EXPLANATORY
NOTES
ABBREVIATIONS:

DBE
dibasic
esters
DMS
dimethyl
succinate
DMG
dimethyl
glutarate
DMA
dimethyl
adipate
h
hour(
s)
SD
standard
deviation
Dibasic
Esters:
in
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
Table
1:
Permeability
parameters
for
individual
DBE
homologues
Rat
DMS
DMG
DMA
Mean
SD
Mean
SD
Mean
SD
Penetration
rate
(
pg/
cm h/
h)
3859.3
1750.6
4542.4
235I
.4
3131.8
1414.1
Lag
time
(
h)
­
0.40
1.51
­
2.79
3.34
­
1.12
2.04
Permeability
coefficient,
KP
(
cmW
3.47x
IO3
1.57x
lo3*
4.18x
IO 
2.16x
IO3*
2.98x
lo3
1.34x
lW3*

Human
DMS
DMG
DMA
Mean
SD
Mean
SD
Mean
SD
Penetration
rate
(
pg/
cm*/
h)
113.0
39.1
103.5
44.0
79.5
35.6
Lag
time
(
h)
0.26
0.48
0.64
0.22
0.60
0.40
Permeability
coefficient.
KP
(
c&)
1.02
ioJ
3.52
9.53
4.05
7.56
10 ~
3.39
Ratio:
Rat
Kp
f
Human
Kp
34.2
43.9
39.4
*
Kp
values
within
a
species
were
not
statistically
different
from
one
another
(
p
>
0.05).
Kp
values
for
each
homologue
between
species
were
statistically
different
from
one
another
(
p
<
0.05).

­
26­
Dibasic
Esters:
In
Vitro
Dermal
Permeability
­
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
Table
2:
Permeability
parameters
for
DBE
homologues
in
the
1:
3:
1
blend
@
MS:
DMG:
DMA)

Penetration
rate
(
clglcm2/
h)

.
Lagtime
(
h)

Permeability
coefficient,
KP
(
c&)

Penetration
rate
(
ps/
cmz/
h)

Lag
time
(
h)

Permeability
coefficient,
KP
(
Ch)

Ratio:
Rat
Kp
I
Human
Kp
Rat
DMS
DMG
DMA
Mean
SD
Mean
SD
Mean
SD
571.7
203.0
1571.0
541.0
507.0
205.0
0.15
0.47
0.12
0.44
0.12
0.53
2.79x
lW3
9.91x
lo4*
2.44x
8.41
x
IO+
2.12
103
8.56
104*

Human
DMS
DMG
DMA
Mean
SD
Mean
SD
Mean
SD
24.2
14.3
108.7
59.6
16.3
7.73
0.28
0.35
0.09
0.22
0.28
0.34
1.18x
10'
6.99x
lUs*
1.69x
10*
9.27x
lo"*
6.81x
lo5
3.23x
lo­'*

23.6
14.5
31.1
*
Kp
values
within
a
species
were
not
statistically
different
from
one
another
(
p>
0.05).
Kp
values
for
each
homologue
between
species
were
statistically
different
from
one
another
(
p
c0.05).

­
27­
Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
KD)
in
Rat
and
Human
Skin
DuPont­
5295
FIGURES
­
28
­
Dibaiic
Esters:
In
VitroDermal
Permeability
 
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
EXPLANATORY
NOTES
ABBREVIATIONS:

DBE
dibasic
esters
DMS
dimethyl
succinate
DMG
dimethyl
glutarate
DMA
dimethyl
adipate
­
29­
Dibasic
Esters:
In
VitroDermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
Figure
1:
Individual
DBE
homologues­
comparison
of
permeability
coefficients
(
Kp)
for
rat
and
human
skin
7.
OOE­
03
6.00E­
03
T
5.00E­
03
4.
O0E­
03
0
Y
2
3.00E­
03
2.00E­
03
1.00E­
03
O.
OOE+
OO
DMS
DMG
DMA
­

30il
i
.
Dibasic
Esters:
In
Vitro
Dermal
Permeability
.
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
Figure
2:
DBE
1:
3:
1
(
DMS:
DMG:
DMA)
blend
­
comparison
of
permeability
coefficients
2.50E­
03
Ih
2
2.00E­

03c
1
0Rat
v
69Humany"
150E­
03
t
5.00E­
04
DMS
DMG
DMA
­
31
­
a.

Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
Figure
3:
A
comparison
of
permeability
coefficients
(
Kp)
for
the
individual
DBE
homologues
and
the
homologues
in
the
1:
3:
1
(
DMS:
DMG:
DMA)
blend
for
rat
skin
7.00E­
03
6.
OOE­
03
5.00E­
03
4.00E­
03
5
v
6
@
3.
OOE­
03
2.
OOE­
03
1.00E­
03
O.
OOE+
OO
I
l­­­­­­
r
IT
I
0
Individual
DMS
DMG
DM4
Kp
values
were
not
statistically
different
from
one
another
(
p
>
0.05)

­
32
­

I/
I
Dibasic
Esters:
In
Vitro
Dermal
Permeability
.
Coefficients(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
Figure
4:
A
comparison
of
permeability
coefficients
(
Kp)
for
the
individual
DBE
homologues
and
the
homologues
in
the
1:
3:
1
@
MS:
DMG:
DMA)
blend
for
human
skin
­
2.5OE­
04
2.00E
04
A
f
0Individual
v
1.50E­
04
2
1.00E­
04
5.00E­
05
0.00E+
00
DMS
DMG
DMA
Kp
values
were
not
statistically
different
from
one
another
(
p
>
0.05)

­
33

P
Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
APPENDICES
­
34
­
,
.
i
.
Dibasic
Esters:
In
Vitro
Dermal
Permeability
.
Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
APPENDICES
EXPLANATORY
NOTES
ABBREVIATIONS:

DBE
dibasic
esters
DMS
dimethyl
succinate
DMG
dimethyl
glutarate
DMA
dimethyl
adipate
h
hour(
s)
SD
standard
deviation
­
3s
­
1'

Dibasic
Esters:
Zn
Vitro
Dermal
Permeability
Coefficients(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
Appendix
A
Permeability
parameters
for
the
individual
DBE
homologues
­
individual
data
for
DMS,
DMG,
and
DMA
when
applied
to
rat
and
human
skin
­
36­
I
Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients(
Kp)
in
Rat
and
Human
Skin
Protocol
group
Species
Test
Material
Cell
ID
cell
1
cell
2
cell
3
cell
5
cell
6
cell
7
Protocolgroup
Species
Test
Material
Cell
ID
cell
8
cell
9
cell
11
cell
12
cell
13
cell
14
Protocolgroup
Species
Test
Material
Cell
ID
cell
1
cell
3
cell
4
cell
5
cell
6
cell
7
DMS
Specimen
ID
659693
659694
659695
659697
659693
659694
Mean
SD
DMG
Specimen
ID
659693
659696
659693
659694
659695
659696
Mean
SD
DMA
Specimen
ID
659693
659694
659694
659693
659697
659696
Mean
SD
Penetrationrate
(
ug/
cm2/
h)
1719.5
6169.1
5236.5
3579.8
2078.6
4372.7
3859.3
1750.6
Penetration
rate
(
ug/
cm2/
h)
1943.6
8136.2
1972.4
5030.6
4565.0
5606.6
4542.4
2351.4
Penetration
rate
(
ug/
cm2/
h)
1577.8
2603.0
4124.6
1509.0
4S36.0
4440.6
3131.8
1414.1
DuPont­
S295
KP
Lag
time­
(
crnlh)
(
h)
1.55E­
03
0.17
5.55
E­
03
0.69
4.71
E­
03
­
2.64
3.22E­
03
­
1.95
1.87E­
03
0.35
3.93E­
03
0.97
3.47E­
03
­
0.40
1.57E­
03
1.51
KP
Lag
time
(
cmlh)
(
h)
1.79E­
03
0.23
7.49503
­
5.74
1.82E­
03
0.17
4.63E­
03
0.35
4.20E­
03
­
6.15
5.16E­
03
­
5.62
4.18E­
03
­
2.79
2.16E­
03
3.34
KP
Lagtime
(
cm/
h)
(
h)
1.50E­
03
0.18
2.48E­
03
0.71
3.92
E­
03
­
2.42
1.44E­
03
0.44
4.31
E­
03
­
1.07
4.22E­
03
­
4.55
2.98E­
03
­
1.12
1.34E­
03
2.04
­
37­
­­
Dibasic
Esters:
In
VimDermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
­
r­­

Test
Material
Cell
ID
cell
1
cell
2
cell
3
cell
5
cell
6
cell
7
Protocolgroup
Test
Material
Cell
ID
cell
8
cell
9
cell
11
cell
12
cell
13
cell
14
DMS
1
Specimen
ID
HCMT­
24A
HCFT­
25A
HCFT­
26A
HCFT­
28A
HCMT­
24A
HCFT­
25A
Mean
SD
Specimen
ID
HCFTP6A
HCMT­
27A
HCMT­
24A
HCFT­
25A
HCFT­
26A
HCMT­
27A
Mean
so
Penetration
rate
(
ug/
cm2/
h)
86.9
104.1
175.5
136.7
63.9
110.7
113.0
39.1
Penetration
rate
(
ug/
cm2/
h)
109.6
69.2
3024.6
85.5
177.2
76.1
103.5
44.0
DuPont­
5295
KP
Lag
time
(
cm/
h)
(
h)
7.82E­
05
­
0.56
9.36E­
05
0.34
1.58E­
04
0.76
1.23E­
04
0.04
5.75E­
05
0.31
9.96E­
05
0.68
1.02E­
04
0.26
3.52E­
05
0.48
KP
Lag
time
(
cm/
h)
(
h)
1.01E­
04
0.61
6.36E­
05
0.78
2.78E­
03
­
4.21
7.86E­
05
0.35
1.63E­
04
0.92
7.01E­
05
0.52
9.53E­
05
0.64
4.05E­
05
0.22
Note:
Cell
11
excluded
from
calculations
of
mean
and
SD
as
it
was
not
representative
Protocolgroup
Test
Material
Penetration
rate
KP
Lagtime
Cell
ID
cell
1
cell
2
cell
3
cell
4
cell
6
cell
7
Specimen
ID
HCMT­
24A
HCFT­
25A
HCFT­
26A
HCMT­
27A
HCFT­
25A
HCFT­
26A
Mean
SD
(
ug/
cm*/
h)
(
cmh)
(
h)
69.5
6.61E­
05
0.27
56.7
5.39E­
05
0.65
115.5
1.1OE­
04
0.38
116.6
1.11E­
04
1.36
26.0
2.47E­
05
0.40
93.1
8.85E­
05
0.52
79.5
7.56E­
05
0.60
35.6
3.39E­
05
0.40
­
38
­
Dibasic
Esters:
In
VitroDermal
Permeability
~

Coefficients
(
Kp)
in
Rat
and
Human
Skin
DuPont­
5295
Appendix
B
Permeability
parameters
for
the
individual
DBE
homologues
in
the
1:
3:
1
(
DMS:
DMG:
DMA)
blend
­
individual
data
for
DMS,
DMG,
and
DMA
when
applied
to
rat
and
human
skin
­
39­
Dibasic
Esters:
In
Vitro
Dermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
Protocol
group
Species
Test
Material
Cell
ID
cell
8
cell
9
cell
10
cell
11
cell
13
cell
14
Protocol
group
Species
Test
Material
Cell
ID
cell
8
cell
9
cell
10
cell
11
cell
13
cell
14
Protocol
group
Species
Test
Material
Cell
ID
cell
8
cell
9
cell
10
cell
11
cell
13
cell
14
DMS
Specimen
ID
659693
659694
659693
659694
659696
659694
Mean
SD
DMG
Specimen
IO
659693
659694
659693
659694
659696
659694
Mean
SD
DMA
Specimen
ID
659693
659694
659693
659694
659696
659694
Mean
SD
Penetration
rate
(
ug/
cm*/
h)
358.9
865.2
326.8
604.6
588.2
686.8
571.7
203.0
Penetration
rate
(
ug/
cm2/
h)
1055.1
2323.7
846.0
1620.6
1733.0
1847.5
1571.
O
541.
O
Penetration
rate
(
ug/
cm2h)
305.9
813.8
248.6
531.2
567.7
574.4
507.0
205.0
DuPont­
5295
KP
Lag
time
(
cmh)
(
h)
1.75E­
03
0.23
4.22E­
03
­
0.37
1.59E­
03
0.66
2.95E­
03
0.10
2.87E­
03
'
­
0.39
3.35E­
03
0.68
2.79E­
03
0.15
9.91E­
04
0.47
KP
Lagtime
­!

(
cmh)
(
h)
1.64E­
03
0.24
t:

3.61E­
03
­
0.38
1.31E­
03
0.56
2.52E­
03
0.08
2.69E­
03
­
0.38
2.87E­
03
0.62
2.44E­
03
0.12
8.41E­
04
0.44
KP
Lag
time
­

(
Cmlh)
(
h)
1.28E­
03
0.29
3.40E­
03
­
0.54
1.04E­
03
0.52
2.22E­
03
0.1
1
2.37E­
03
­
0.45
2.40E­
03
0.79
2.1
2E­
03
0.12
8.56E­
04
0.53
­
40­
Protocol
group
Test
Material
Dibqsic
Esters:
In
VitroDermal
Permeability
Coefficients
(
Kp)
in
Rat
and
Human
Skin
Protocolgroup
Test
Material
Cell
ID
Specimen
ID
cell
8
HCMT
27­
A
cell
10
HCFT­
25A
cell
11
HCFT­
26A
cell
12
HCMT­
27A
cell
13
HCFT­
28A
cell
14
HCFT­
25A
Mean
SD
Protocol
group
Test
Material
Cell
ID
Specimen
ID
cell
8
HCMT
27­
A
cell
10
HCFT­
25A
cell
11
HCFT­
26A
cell
12
HCMT­
27A
cell
13
HCFT­
28A
cell
14
HCFT­
25A
Mean
SD
Protocolgroup
Species=]
s
peciesl­
1
Cell
ID
Specimen
ID
cell
8
HCMT
27­
A
cell
10
HCFT­
25A
cell
11
HCFT­
26A
cell
12
HCMT­
27A
cell
13
HCFT­
28A
cell
14
HCFT­
25A
Mean
SD
Penetration
rate
(
ug/
cm2/
h)
25.2
15.1
34.9
11.8
46.7
11.4
24.2
14.3
­

Penetration
rate
(
ug/
cm2/
h)
129.7
37.1
145.7
56.5
196.2
87.2
108.7
59.6
Penetrationrate
(
ug/
cm2/
h)
18.8
9.92
21.3
10.9
28.1
8.73
16.3
7.73
DuPont­
5295
KP
Lag
time
(
cm/
h)
(
h)
1.23E­
04
0.60
7.39E­
05
0.18
1.70E­
04
0.50
5.74
E­
05
0.62
2,28504
'
­
0.25
5.55E­
05
0.04
1.
I
8E­
04
0.28
6.99
E­
05
0.35
KP
Lag
time
(
cmlh)
(
h)
2.02
E­
04
0.24
5.76E­
05
0.26
2.26E­
04
0.19
8.78
E­
05
0.25
3.05E­
04
­
0.24
1.35E­
04
­
0.13
1.69E­
04
0.09
9.27E­
05
0.22
KP
Lag
time
(
cm/
h)
(
h)
7.86E­
05
0.58
4.14E­
05
0.22
8.92
E­
05
0.50
4.55E­
05
0.51
1.17E­
04
­
0.32
3.65
E­
05
0.21
6.81
E­
05
0.28
3.23E­
05
0.34
­
41
­