[Study of hepatic drug metabolism. For a rationalization of a new molecular development]

Interindividual variability of hepatic metabolism of drugs may be responsible for decrease in efficacy, increase in the incidence and severity of adverse effects or drug-interactions. This variability may be due to hepatic drug interaction, specific physio-pathologic condition or genetic polymorphism. Search for variability of hepatic metabolism and the factors determining this variability during the pre-clinical and clinical development of new drug contributes to an individual optimization of treatment during clinical research and after introduction into the market. This strategy results in an improvement of the benefit-risk ratio. The various methodological approaches to the study of hepatic metabolism during the successive phases of drug development and the integration of these studies in the clinical development plan of a new drug are discussed in this paper.