Low Rate of Severe Injury from Dermal and Ocular Irritation Tests and the Validity of Using Fewer Animals

Abstract

Current U.S. and Japanese regulatory guidelines mandate the use of at least six animals for dermal and ocular irritation testing, while EEC/OECD guidelines require only three animals. An analysis of data from this laboratory in general supports the use of as few as three animals for acute irritancy testing. Data from a series of 140 dermal and 118 ocular irritation tests were examined to determine injury rates associated with testing, and to generate six-, five-, four-, three-, and two-rabbit primary dermal irritation indices for dermal tests and to categorize ocular tests similarly. Results were then examined to determine whether fewer animals could have been used to obtain findings similar to those originally noted with six rabbits. These results suggest that the number of animals used in dermal and ocular irritation testing can be reduced, especially if a sequential approach involving a preliminary in vitro/SAR test is taken. In addition, low rates of severe injury were evident for dermal and ocular irritation tests, as well as low discomfort rates for ocular irritation tests using a topical anesthetic. Using a low level of dermal irritation as a screen for ocular testing could reduce injury and discomfort rates further.

Keywords

Irritation tests Toxicity methods Reproducibility Rabbits Toxicity Animal welfare

References

Atkinson KA , Fentem JH , Clothier RH , Balls M . (1992). Alternatives to ocular testing in animals. Lens Eye Toxic Res 9:247–58.

Calvin G . (1992) New approaches to the assessment of eye and skin irritation. Toxicol Lett 64–65:157–64.

de Haan P , Heemskerk AE , Gerritsen A , et al. (1993) Comparison of toxicity tests on human skin and epidermoid (A431) cells using free fatty acids as test substances. Clin Exp Dermatol 18:428–33.

Derelenko MJ , Finegan CE , Dunn BJ . (1993) Reliability of using fewer rabbits to evaluate dermal irritation potential of industrial chemicals. Fundam Appl Toxicol 21:159–63.

De Sousa DJ , Rouse AA , Smolon WJ . (1984) Statistical consequences of reducing the number of rabbits utilized in eye irritation testing: data on 67 petrochemicals. Toxicol Appl Pharmacol 76:234–42.

EEC . (1988) Methods for the determination of toxicity. Official J Eur Commun 31:L133.

Goldberg AM , Silber PM . (1992) Status of in vitro ocular testing. Lens Eye Toxic Res 9:161–92.

Green S , Chambers WA , Gupta KC , et al. (1993) Criteria for in vitro alternatives for the eye irritation test. Food Chem Toxicol 31:81–5.

Hatoum NS , Leach CL , Talsma DM , Gibbons RD , Garvin PJ . (1990) A statistical basis for using fewer rabbits in dermal irritation testing. J Am Coll Toxicol 9:49–60.

10.

Hume RD. (1990) Development of a short-term in-vitro dermal toxicity screening test utilizing human cells: phase 1. National Technical Information Service, Report NTIS/AD-B160 703/5, Washington, D.C.

11.

Hurley PM , Chambers WA , Green S , et al. (1993) Screening procedures for eye irritation. Food Chem Toxicol 31:87–93.

12.

Ministry of Agriculture, Forestry and Fisheries. (1984) Toxicologic studies on agricultural chemicals. Japan: Agriculture Production Bureau, Notification 3850 59 Noh San, Japan.

13.

Nixon GA , Bannan EA , Gaynor TW , Johnston DH , Griffith JF . (1990) Evaluation of modified methods for determining skin irritation. Regul Toxicol Pharmacol 12:127–36.

14.

Organization for Economic Co-operation and Development. (1987) Guideline for Testing of Chemicals. Feb 24, 1987. Paris, France.

15.

Rougier A , Cottin M , de Silva O , et al. (1992) In vitro methods: their relevance and complementarity in ocular safety assessment. Lens Eye Toxic Res 9:229–45.

16.

Sugai S , Murata K , Kitagaki T , Tomita I . (1991) Studies on eye irritation caused by chemicals in rabbits. II. An in vitro testing method using rat red blood cells for the prediction of eye irritation potential of chemicals. J Toxicol Sci 16:131–44.

17.

Talsma DM , Leach CL , Hatoum NS , Gibbons RD , Rober JC , Garvin PJ . (1988) Reducing the number of rabbits in the Draize eye irritancy test: a statistical analysis of 155 studies conducted over 6 years. Fundam Appl Toxicol 10:146–53.

18.

USCPSC. (1990a) Consumer Products Safety Commission, sect 1500.41: method of testing primary irritant substances. 16 CFR ch II (Jan 1, 1990 ed). U.S. Government Printing Office, Washington. D.C.

19.

USCPSC. (1990b) Consumer Products Safety Commission, sect 1500.42: test for eye irritants. 16 CFR ch II (Jan 1, 1990 ed). U.S. Government Printing Office, Washington, D.C.

20.

USEPA. (1988) Pesticide Assessment Guidelines, Subdivision F, Hazard Evaluation: Human and Domestic Animals, Series 81–5, Dermal Irritation Addendum 3 on Data Reporting. U.S. Government Printing Office, Washington, D.C.

21.

USEPA. (1989a) Pesticide Assessment Guidelines, Subdivision F, Hazard Evaluation: Human and Domestic Animals, Series 83–4, Primary Eye Irritation. U.S. Government Printing Office, Washington, D.C.

22.

USEPA. (1989b) Pesticide Assessment Guidelines, Subdivision F, Hazard Evaluation: Human and Domestic Animals, Series 83–5, Primary Dermal Irritation. U.S. Government Printing Office, Washington, D.C.

23.

USEPA. (1994) Label Review Manual, EPA737–B–95–001, ch 8. Registration Division, Office of Pesticide Programs. U.S. Government Printing Office, Washington, D.C.

24.

Wilcox NL . (1992) The status of eye irritancy testing: a regulatory perspective. Lens Eye Toxic Res 9:259–71.