The necessity of biokinetic information in the interpretation of in vitro toxicity data

Data derived from in vitro toxicity studies are not directly applicable in an assessment of the toxicity of compounds in intact organisms. The major limitation is the lack of knowledge of biokinetic behaviour in vivo. Since the toxicity of a compound will be determined by the critical concentration (or other dose metric) of the critical compound (or a metabolite thereof) at the critical site of toxic action, biokinetic behaviour must be taken into account. Possibilities of biokinetic modelling on the basis of in vitro and other non-animal data are discussed, and the application of the results in hazard and risk-assessment schedules is considered.