This course is a description of the bases of therapeutic drug monitoring by discussing the pharmacokinetics of drugs following intravenous administration, intravenous infusion, oral and/or extra vascular administration of drugs that undergo first-order and zero-order elimination kinetics, emphasizing one-compartment and two- compartment models. The basis of bioavailability and bioequivalence studies will be emphasized. This science is considered the basis of therapeutic drug monitoring.