Pharmacokinetics: The Role of Compartmental Models

Abstract

After an introduction in which terms commonly used in the pharmacokinetics literature are defined, the role of linear, time -invariant compartmental models in pharmacokinetics is discussed. It is found that, while such models are useful for the simultaneous modelling of drug and metabolite kinetics, there is a lack of motivation for using them to describe drug kinetics alone. Three examples of nonlinear models are then discussed. Ihese model plasma responses to an orally-administered input when the input rate departs from first-order form, plasma responses when the elimination pathway is capacity-limited and the relationship between pharmacokinetics (drug in blood) and pharmacodynamics (pharmacological response).