THE CLASSIFICATION OF SKIN IRRITANTS BY HUMAN PATCH TEST

The human 4 hour patch test provides an opportunity to identify substa nces with significant skin irritation potential without recourse to th e use of animals. The protocol is designed to avoid the production of more than mild irritant reactions and meets the highest ethical standa rds. This paper provides the background to the development of the meth od and comments on its performance in the light of recent intra-and in ter-laboratory investigations. In particular, the value of the method in providing 'gold standard' data for the identification of those subs tances (or preparations) which should, or should not, be classified as irritant to skin in European legislation is discussed. On the basis o f the published data and supplementary investigations, recommendations are made on both the conduct and interpretation of the human 4 hour p atch test. Finally, the lack of any necessity for formal validation of this assay is addressed. (C) 1997 Elsevier Science Ltd.