Standard Practice for Guinea Pig: Split Adjuvant and Closed Patch Testing for Contact Allergens

Abstract

5.1 In selecting a material for human contact in medical applications, it is important to ensure that the material will not stimulate the immune system to produce an allergic reaction under relevant exposure conditions. Extractable chemicals produced by skin contact or during physiological exposures may cause allergic reactions. Therefore, this practice provides for evaluations of solid or semisolid dosage forms using material extracts or direct evaluation of the test article. The rationale for this animal model is based on the fact that the guinea pig has been shown to be an appropriate animal model for predicting human contact dermatitis. Its tractable nature, its availability from reputable suppliers, the historical database of information already acquired using this species, and the correlation of such results to data on known human allergens all contribute to its widespread use for allergenicity studies (1-5).4 5.2 The need for sensitization procedures other than the maximization test (Test Method F720) is based on: (1) the need for a route of exposure more similar to use conditions; (2) concern over the use of adjuvant because of its recruitment of cell types to the test site which are not typically involved in immunologic reactions, and because of the discomfort this causes in the animals; (3) absence of a proper FCA irritant control group in the traditional maximization design; and (4) the frequency of false positives often encountered with the GPMT. Both of these tests are internationally accepted (1).