TWO COMPARTMENT MODEL

In the two compartment model, the body is considered to consist of two compartments, the central compartment and the peripheral compartment.

• The central compartment comprises those tissues that are well perfused, for example the heart, kidneys and liver. Drug distributes rapidly into this compartment.
• The peripheral compartment comprises those tissues that are less well perfused, for example muscle, fat and skin. Drug distributes more slowly into this compartment.

It is assumed that the drug distributes between the two compartments but that the drug is eliminated only from the central compartment. The model can be illustrated as shown below.