Local irritation/corrosion testing strategies: Development of a decision support system for the introduction of alternative methods

The notification procedure for new chemicals of the European Union (EU) req uires protocols on physicochemical and toxicological tests for the evaluati on of physicochemical properties and probable toxic effects of each notifie d substance. In order to reduce the amount of animal testing, alternative m ethods should be introduced into toxicity testing. Therefore, we have devel oped a rule-based decision support system (DSS) for the prediction of the l ocal corrosive/irritant properties of new chemicals. To this end, data on m ore than 1000 substances were examined, which resulted in approximtely 180 "exception-rules" of the kind IF (physicochemical property) A THEN not (tox ic) Effect B. In addition, the structural formulae of the chemicals were an alysed, which resulted in approximately 160 "structure-rules" of the kind I F Substructure A THEN Effect B. The DSS can predict (based on theoretical s tructure-activity relationships) whether a chemical produces: a) corrosive effects (i.e. no testing is necessary; b) might have corrosive effects (i.e , no animal testing, in vitro tests are suitable); and c) will produce no e ffects or only marginal effects (i.e. animal tests are necessary based on c urrent EU legislation for hazard assessment purposes). In addition, the DSS provides reliable data for legal classification and labelling based on a s pecific result.