Compartment (pharmacokinetics)

Inpharmacokinetics,acompartmentis a defined volume ofbody fluids,typically of thehuman body,but also those of other animals with multipleorgan systems.The meaning in this area of study is different from the concept ofanatomic compartments,which are bounded byfasciae,the sheath offibrous tissuethat enclosemammalianorgans. Instead, the concept focuses on broad types of fluidic systems. This analysis is used in attempts to mathematically describe distribution of small molecules throughout organisms with multiple compartments. Variousmulti-compartment modelscan be used in the areas of pharmacokinetics andpharmacology,in the support of efforts indrug discovery,and inenvironmental science.

In humans and related organisms, there are five major body compartments: theblood plasma,interstitial fluids,fat tissues,intracellular fluids,andtranscellular fluids,the latter of which includes fluids in thepleural(peritoneal) cavity.The relative percents of body mass of these are included in the following table.

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

See also

• Fluid compartments