Compartment (pharmacokinetics)

In pharmacokinetics, a compartment is a defined volume of body fluids. It is distinguished from anatomic compartments, which are bounded by fasciae. It is used in multi-compartment models.

Examples

There are five major body compartments:

• blood plasma
• interstitial fluid
• fat tissue
• intracellular fluid
• transcellular fluid

The transcellular compartment includes fluids in the pleural cavity or peritoneal cavity.

Comparison table

Compartment	estimated % of body mass
blood plasma	5
interstitial fluid	16
fat tissue	20 (see also body fat percentage)
intracellular fluid	35
transcellular fluid	2

Mnemonic: 60-40-20-15-5: % of TBW, Intracellular fluid, Extracellular fluid, interstitial fluid, plasma