IN VITRO METHODS TO MEASURE TOXICITY OF CHEMICALS

Rapid screening of industrial compounds for toxicity will require high-throughput in vitro assays with which to select candidate compounds for more intensive animal testing. The purpose of this study, sponsored by the National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) and the European Centre for the Validation of Alternative Methods (ECVAM), is to evaluate the utility of in vitro cytotoxicity assays for estimating the starting dose for the rat oral acute toxicity test, thus reducing and refining the use of animals in the toxicological assessment of industrial chemicals of military interest. The three-phase study will evaluate 72 coded chemicals with well-defined in vivo acute toxicity data, representing a wide range of toxicity and use categories for their ability to induce cytotoxicity as determined by neutral red uptake (NRU) in two cultured cell systems [mouse fibroblast (BALB/c) 3T3 and normal human keratinocytes (NHK)]. Phase I and II studies have been completed under GLP (Good Laboratory Practice) – compliance and the data are presented here