Physiological plasma compartment (Plasma)

The physiological plasma compartment is the intravascular fluid component of the blood, constituting approximately 55% of total blood volume. It functions as the primary transport medium for oxygen, nutrients, hormones, and metabolic waste products, while also maintaining osmotic pressure and acid-base balance (StatPearls, 2023). In the context of pharmacology, it is typically defined as the central compartment in pharmacokinetic modeling, representing the initial volume of distribution for systemically administered drugs (Principles of Clinical Pharmacology, 2012). While not a specific molecular target like a receptor or enzyme, its physiological state determines drug protein binding and systemic concentration. Pathological changes in plasma volume or composition, such as those seen in sepsis or dehydration, can significantly alter the pharmacokinetics of various therapeutic agents (Merck Manual, 2022).

Other names

Blood plasmaIntravascular compartmentCentral compartmentPlasma volume

Serves as the central distribution compartment for systemic drugs; plasma expanders increase intravascular volume by increasing oncotic or osmotic pressure (StatPearls, 2023).