Pharmacokinetics: Model structure and transport systems

Drug transport in pharmacokinetics is based on material exchanges between and irreversible losses from compartments. The compartment serves as a homogeneous anatomic and physiological region, representing one or more organs, with time and spatial dependencies in drug concentrations possible. Normally, drug concentrations within each compartment are assumed to be homogeneous, and only time dependencies in concentration are sought. The mathematical description and inherent assumptions of drug transport within each compartment determine the type of pharmacokinetic model and analysis.