Compartmental Pharmacokinetic Models

Pharmacokinetic modeling is a tool that helps drug developers, clinicians, and health care professionals in general to understand and/or predict the time-course of a drug within the body (and/or specific body compartments), and to make informed decisions related to the dosing scheme to maximize the efficacy and minimize adverse drug reactions. Early pharmacokinetic studies are also helpful to estimate critical pharmacokinetic parameters and to assist hit-to-lead and lead-optimization programs within pharmaceutical companies. Compartmental modeling is a model-based method in which the body is represented by one or more hypothetical compartments, each of them behaving homogeneously from a pharmacokinetic perspective. In classic compartmental analysis, these compartments do not represent actual physiological tissues. In contrast, physiologically-based pharmacokinetic (PBPK) modeling considers one compartment for each pharmacokinetically relevant organ or tissue to explain the absorption and disposition of a drug. This chapter serves as an introduction to the one- and two-compartment pharmacokinetic models.