drug absorption mechanisms

Bioavailability in Pharmacology: Definition, Types, Measurement, and Clinical Importance (2026) Pharmacokinetics—the study of how the body affects a drug—rests upon four fundamental processes: absorption, distribution, metabolism, and excretion. Among these, bioavailability represents the most critical determinant of therapeutic efficacy, serving as the gateway through which drug molecules enter systemic circulation and ultimately reach their sites…