.... United States Environmental Protection Agency Prevention, Pesticides and Toxic Substances (7101) EPA 712–C–96–251 June 1996


# Health Effects Test Guidelines
OPPTS 870.8245 Dermal Pharmacokinetics of DGBE and DGBA

‘‘Public Draft’’

### i 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 theNational 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 proceduresthat 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 theEPA 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.’’

### 1 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 speciesfor 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 14 C-labeled DGBE and DGBA. The use of 14 C-DGBE and 14 C-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.

### 2 (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 14 C-DGBE.
(B) Eight animals should be dosed once dermally with the high dose of 14 C-DGBE.
(C) Eight animals should be dosed once dermally with the low dose of 14 C-DGBA.
(D) Eight animals should be dosed once dermally with the high dose of 14 C-DGBA.
(E) The high and low doses of 14 C-DGBE and 14 C-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 90percent 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 14 C 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.

### 3 (ii) Biotransformation after dermal dosing. Appropriate qualitativeand 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 14 C-DGBE and 14 C-DGBA.
(v) Quantity of isotope, together with percent recovery of the administered dose, in feces and urine.
(vi) Biotransformation pathways and quantities of DGBE andmetabolites in urine collected after administering single high and low dermal doses to rats.