Drug diffusion

Drug diffusion is the spontaneous, passive movement of drug molecules from a region of higher concentration to one of lower concentration, typically across a biological membrane (StatPearls, https://www.ncbi.nlm.nih.gov/books/NBK557405/). This process is driven by a concentration gradient and does not require cellular energy or specialized transport proteins, distinguishing it from active transport (Merck Manual, https://www.merckmanuals.com/professional/clinical-pharmacology/pharmacokinetics/drug-absorption). The rate of diffusion is influenced by the drug's physicochemical properties, including its lipophilicity, molecular weight, and ionization state, as described by Fick's Law (PubMed, https://pubmed.ncbi.nlm.nih.gov/11770221/). In a clinical context, diffusion is a fundamental component of pharmacokinetics, determining how a drug is absorbed in the gastrointestinal tract and distributed throughout various body compartments (NIH, https://www.nigms.nih.gov/education/fact-sheets/Pages/pharmacokinetics.aspx). Because it is a physical process rather than a biological macromolecule, 'Drug diffusion' is not considered a therapeutic target, although drug delivery systems are often designed to optimize or control this process (Wikipedia, https://en.wikipedia.org/wiki/Diffusion).

Other names

Passive diffusionMolecular diffusionSimple diffusionTransmembrane permeation

Drug diffusion is a physicochemical process, not a drug mechanism of action on a specific molecular target. It involves the movement of molecules down a concentration gradient across biological membranes (StatPearls).