What is the concept of compartment models in pharmacokinetics?

The concept of compartment models in pharmacokinetics refers to a framework that represents how a drug is distributed throughout the body by dividing the system into distinct compartments. These compartments can be thought of as areas where the drug may be present in varying concentrations, influenced by factors such as blood flow, tissue permeability, and the physical and chemical properties of the drug.

In a typical compartment model, the body may be simplified into one, two, or three compartments (requiring different degrees of complexity). The one-compartment model assumes that the drug distributes rapidly and equally throughout the body, allowing calculations based on a single concentration. The two-compartment model introduces an additional layer, distinguishing between central (vascular) and peripheral (tissue) compartments, providing a more accurate reflection of drug kinetics in real physiological systems.

Using compartment models allows pharmacokineticists to predict how the concentration of a drug changes over time, helping in dosaging decisions, understanding therapeutic effects, and assessing elimination patterns. Therefore, the focus of compartment models is primarily on drug distribution across these defined compartments, making this option the correct choice.