ABSTRACT
Metabolism of xenobiotics is essential for detoxification and removal of foreign substances from the body. In general, the defensive mechanisms are to convert the xenobiotic into one or more polar compounds so that the metabolites can readily be eliminated from the body. In order to maximize the desired effects of a drug while minimizing its untoward effects in the patient population, a thorough understanding of pharmacokinetics/dynamics of the drug and its metabolites is required for rational drug development and proper dosing. The metabolite models used in the simulations described the formation of a single metabolite with the elimination of metabolite being rate-limited by its formation in the body or by its excretion from the systemic circulation. Granted that the activity of the metabolite(s) has been established as important for the assessment of bioequivalence, problems often arise with respect to measurement of the metabolite.
