Toxicity testing of new compounds is essential for drug development process. The preclinical toxicity testing on various biological systems reveals the species-, organ- and dose- specific toxic effects of an investigational product. The toxicity of substances can be observed by (a) studying the accidental exposures to a substance (b) in vitro studies using cells/ cell lines (c) in vivo exposure on experimental animals. This review mainly focuses on the various experimental animal models and methods used for toxicity testing of substances. The pre-clinical toxicity testing helps to calculate "No Observed Adverse Effect Level" which is needed to initiate the clinical evaluation of investigational products.
Keywords: No Observed Adverse Effect Level; Toxicity; rodents.