United States

Environmental Protection

Agency

Prevention, Pesticides

and Toxic Substances

(7101)

EPA712–C–96–251

June 1996

Health Effects Test

Guidelines

OPPTS 870.8245

Dermal

Pharmacokinetics of

DGBE and DGBA

‘‘Public Draft’’
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INTRODUCTION

This guideline is one of a series of test guidelines that have been

developed by the Office of Prevention, Pesticides and Toxic Substances,

United States Environmental Protection Agency for use in the testing of

pesticides and toxic substances, and the development of test data that must

be submitted to the Agency for review under Federal regulations.

The Office of Prevention, Pesticides and Toxic Substances (OPPTS)

has developed this guideline through a process of harmonization that

blended the testing guidance and requirements that existed in the Office

of Pollution Prevention and Toxics (OPPT) and appeared in Title 40,

Chapter I, Subchapter R of the Code of Federal Regulations (CFR), the

Office of Pesticide Programs (OPP) which appeared in publications of the

National Technical Information Service (NTIS) and the guidelines published by the Organization for Economic Cooperation and Development

(OECD).

The purpose of harmonizing these guidelines into a single set of

OPPTS guidelines is to minimize variations among the testing procedures

that must be performed to meet the data requirements of the U. S. Environmental Protection Agency under the Toxic Substances Control Act (15

U.S.C. 2601) and the Federal Insecticide, Fungicide and Rodenticide Act

(7 U.S.C. 136, et seq.).

Public Draft Access Information: This draft guideline is part of a

series of related harmonized guidelines that need to be considered as a

unit. For copies: These guidelines are available electronically from the

EPA Public Access Gopher (gopher.epa.gov) under the heading ‘‘Environmental Test Methods and Guidelines’’ or in paper by contacting the OPP

Public Docket at (703) 305–5805 or by e-mail:

guidelines@epamail.epa.gov.

To Submit Comments: Interested persons are invited to submit comments. By mail: Public Docket and Freedom of Information Section, Office

of Pesticide Programs, Field Operations Division (7506C), Environmental

Protection Agency, 401 M St. SW., Washington, DC 20460. In person:

bring to: Rm. 1132, Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA. Comments may also be submitted electronically by sending

electronic mail (e-mail) to: guidelines@epamail.epa.gov.

Final Guideline Release: This guideline is available from the U.S.

Government Printing Office, Washington, DC 20402 on The Federal Bulletin Board. By modem dial 202–512–1387, telnet and ftp:

fedbbs.access.gpo.gov (IP 162.140.64.19), or call 202–512–0132 for disks

or paper copies. This guideline is also available electronically in ASCII

and PDF (portable document format) from the EPA Public Access Gopher

(gopher.epa.gov) under the heading ‘‘Environmental Test Methods and

Guidelines.’’
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OPPTS 870.8245 Dermal pharmacokinetics of DGBE and DGBA.

(a) Scope—(1) Applicability. This guideline is intended to meet testing requirements of both the Federal Insecticide, Fungicide, and

Rodenticide Act (FIFRA) (7 U.S.C. 136, et seq.) and the Toxic Substances

Control Act (TSCA) (15 U.S.C. 2601).

(2) Background. The source material used in developing this harmonized OPPTS test guideline is the OPPT 40 CFR 795.225 Dermal

Pharmacokinetics of DGBE and DGBA.

(b) Purpose. The purpose of these studies is to determine the absorption of diethylene glycol butyl ether (DGBE) after administration by the

dermal route; the biotransformation of DGBE administered dermally; and

the dermal absorption of DGBE and diethylene glycol butyl ether acetate

(DGBA).

(c) Test procedures—(1) Animal selection—(i) Species. The species

utilized for investigating DGBE and DGBA should be the rat, a species

for which historical data on the toxicity and carcinogenicity of many compounds are available and which is used extensively in percutaneous absorption studies.

(ii) Animals. Adult female Sprague Dawley rats should be used. The

rats should be 7 to 8 weeks old and weigh 180 to 220 g. Prior to testing,

the animals should be selected at random for each group. Animals showing

signs of ill health should not be used.

(iii) Animal care. (A) The animals should be housed in environmentally controlled rooms with 10 to 15 air changes per hour. The rooms

should be maintained at a temperature of 25 ± 2 °C and humidity of

50 ± 10 percent with a 12–h light/dark cycle per day. The rats should be

isolated for at least 7 days prior to use.

(B) During the acclimatization period, the rats should be housed in

cages on hardwood chip bedding. All animals should be provided with

conventional laboratory diets and water ad libitum.

(2) Administration of DGBE and DGBA—(i) Test substances.

These studies require the use of 14C-labeled DGBE and DGBA. The use

of 14C-DGBE and 14C-DGBA is required for the determinations in paragraphs (b) (1), (2), and (3) of this guideline because they will facilitate

the work and improve the reliability of quantitative determinations.

(ii) Dosage and treatment. (A) Two doses of DGBA should be used

in the study, a low dose and a high dose. Three doses of DGBE should

be used in the study, a neat low dose, an aqueous low dose, and neat

high dose. When administered dermally, the high dose level should ideally

induce some overt toxicity such as weight loss. The low dose level should

correspond to a no-observed-effect-level.
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(B) For dermal treatment, the doses should be applied in a volume

adequate to deliver the prescribed doses. The backs of the rats should be

lightly shaved with an electric clipper shortly before treatment. The dose

should be applied with a micropipette on a specific area (for example,

2 cm2) on the freshly shaven skin.

(iii) Washing efficiency study. Before initiation of the dermal absorption studies described in paragraph (c)(2)(iv)(A) of this guideline, an

initial washing efficiency experiment should be performed to assess the

extent of removal of the applied DGBE and DGBA by washing with soap

and water. Groups of four rats should be lightly anesthetized with sodium

pentobarbital. These animals should then be treated with dermal doses of

test substance at the low dose level. Soon after application (5 to 10 min)

the treated animals should be washed with soap and water then housed

in individual metabolism cages for excreta collection. Urine and feces

should be collected at 8, 24, and 48 h following dosing. Collection of

excreta should continue every 24 h if a significant amounts of DGBE,

DGBA, or metabolites continue to be eliminated.

(iv) Determination of absorption, biotransformation, and excretion. (A) Eight animals should be dosed once dermally with the low dose

of 14C-DGBE.

(B) Eight animals should be dosed once dermally with the high dose

of 14C-DGBE.

(C) Eight animals should be dosed once dermally with the low dose

of 14C-DGBA.

(D) Eight animals should be dosed once dermally with the high dose

of 14C-DGBA.

(E) The high and low doses of 14C-DGBE and 14C-DGBA should

be kept on the skin for 24 h. After application, the animals should be

placed in metabolism cages for excreta collection. After 24 h, any test

material remaining on the skin will be washed off and the containment

cell removed. Radiolabeled material in the wash will be accounted for in

the total recovery. Urine and feces should be collected at 8, 24, 48, 72,

and 96 h after dosing, and if necessary, daily thereafter until at least 90

percent of the dose has been excreted or until 7 days after dosing, whichever occurs first.

(3) Observation of animals—(i) Urinary and fecal excretion. The

quantities of total 14C excreted in urine and feces by rats dosed as specified

in paragraph (c)(2)(iv) of this guideline should be determined at 8, 24,

48, 72 and 96 h after dosing, and if necessary, daily thereafter until at

least 90 percent of the dose has been excreted or until 7 days after dosing

(whichever occurs first). Four animals from each group should be used

for this purpose.
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(ii) Biotransformation after dermal dosing. Appropriate qualitative

and quantitative methods should be used to assay urine specimens collected from rats dosed with DGBE as specified in paragraph (c)(2)(iv)

of this guideline. Any metabolite which comprises greater than 10 percent

of the dose should be identified.

(d) Data and reporting—(1) Treatment of results. Data should be

presented in tabular form.

(2) Evaluation of results. All observed results, quantitative or incidental, should be evaluated by an appropriate statistical method.

(3) Test report. In addition to the reporting requirements as specified

in 40 CFR part 792, subpart J, the following specific information should

be reported:

(i) Species, strain, and supplier of laboratory animals.

(ii) Information on the degree (i.e., specific activity for a radiolabel)

and sites of labeling of the test substances.

(iii) A full description of the sensitivity and precision of all procedures used to produce the data.

(iv) Relative percent absorption by the dermal route for rats administered low and high doses of 14C-DGBE and 14C-DGBA.

(v) Quantity of isotope, together with percent recovery of the administered dose, in feces and urine.

(vi) Biotransformation pathways and quantities of DGBE and

metabolites in urine collected after administering single high and low dermal doses to rats.