Two-Compartment Open Model: Overview

Multicompartment pharmacokinetic models illustrate drug distribution and elimination within the body.

The most common type of these models is the two-compartment model that classifies the body tissues into two sections—the central and peripheral compartments.

The central compartment encompasses blood and highly perfused tissues, like the liver, kidneys, etc., that rapidly equilibrate with the drug.

In contrast, the peripheral compartment involves less perfused and slowly equilibrating tissues, like adipose tissue, skin, and muscles.

Depending on tissue perfusion,  the drug is distributed from the central to the peripheral compartment, decreasing the plasma drug concentration. This decrease is expressed biexponentially as the sum of the distribution and elimination processes.

Two-compartment models are further classified into three types based on whether the drug is eliminated from the central, peripheral, or both compartments.