Answer :
Final answer:
The distribution of a drug within the body is described by the 'Volume of Distribution' (VD), which measures the total volume of body fluids where a drug is distributed and is a key concept in pharmacokinetics.
Explanation:
The term used to describe the distribution of a drug within the body is known as the ‘Volume of Distribution’ (VD). This term refers to the total volume of body fluids in which a drug or toxicant is distributed after it is absorbed. The VD can include plasma, interstitial fluid, and intracellular fluid, indicating that the drug has the potential to be distributed across various compartments within the body.
The Volume of Distribution is expressed in liters and gives an insight into how the drug diffuses and equilibrates throughout the body’s tissues and fluids. It is an essential concept in pharmacokinetics, which also encompasses other processes like absorption, biotransformation (metabolism), and excretion.
For instance, if we consider the one-compartment model, it assumes that the drug distributes rapidly and evenly throughout the body, much like a substance would in a single fluid compartment, and is eliminated in a manner proportional to its concentration in the body (‘first-order’ kinetics).
