What is the Origin of Drug Partitioning?

The term is derived from the scientific concept of "partitioning," which means dividing into parts or separating. In a pharmacological context, it applies the chemical principle of a solute distributing itself between two immiscible solvents to the biological system of a drug distributing between blood and tissues.

What is the Mechanism of Drug Partitioning?

The underlying mechanism is governed by the partition coefficient, which quantifies the ratio of the drug's concentration in a nonpolar phase (like fat tissue) to its concentration in an aqueous phase (like plasma). Highly lipophilic, non-ionized drugs readily cross biological membranes and partition extensively into adipose tissue, while highly ionized, hydrophilic drugs tend to remain in the plasma and extracellular fluid. This differential distribution directly impacts the drug's volume of distribution and its half-life.

Drug Partitioning ∞ Area

Drug Partitioning

Meaning

Drug partitioning, a core concept in pharmacokinetics, describes the distribution of a drug between different body compartments or tissues at equilibrium. This phenomenon is dictated by the drug’s physicochemical properties, such as its lipophilicity, ionization state, and its affinity for various plasma and tissue proteins. Understanding this distribution is crucial for predicting the drug’s concentration at its target site and its potential for systemic toxicity.