Physical distribution in tissues and organs

Physical distribution in tissues and organs refers to the fundamental pharmacokinetic process (Distribution) by which a drug or compound is translocated from the systemic circulation into various body fluids and tissues (Merck Manual, 2023). This process is a key component of the ADME framework—Absorption, Distribution, Metabolism, and Excretion—and is influenced by physiological factors such as regional blood flow, organ size, and capillary permeability, as well as the physicochemical properties of the molecule (StatPearls, 'Pharmacokinetics', 2023). It is not a therapeutic target, such as a receptor, enzyme, or ion channel, but rather a description of a substance's movement through the biological system (National Center for Biotechnology Information, 2022). Understanding this distribution is critical for determining the concentration of a drug at its site of action and for assessing the risk of off-target toxicity in non-intended organs (PubMed, PMID: 21873491). In drug development, distribution characteristics are optimized to ensure a favorable therapeutic index and appropriate dosing regimens (FDA ADME Guidelines, 2021).

Other names

Tissue distributionDrug distributionBiodistributionPharmacokinetic distributionVolume of distribution

Not applicable; this is a pharmacokinetic process rather than a molecular target.