Comparative Pharmacokinetics of Biologics Versus Small Molecule Drugs in Disease States

Abstract

Pharmacokinetics (PK) plays a critical role in optimizing drug therapy by elucidating how drugs are absorbed, distributed, metabolized, and eliminated in the body. Biologics and small-molecule drugs, two major classes of therapeutics, differ significantly in their molecular structure and pharmacokinetic behavior, particularly in pathological conditions. This article provides a comparative analysis of the pharmacokinetics of biologics versus small-molecule drugs in various disease states, highlighting how disease-associated physiological changes influence drug disposition. Key differences in absorption routes, metabolic pathways, distribution patterns, and clearance mechanisms are discussed, along with the impact of factors such as inflammation, organ dysfunction, and immunogenicity on drug kinetics. Understanding these distinctions is essential for tailoring dosing regimens, improving therapeutic efficacy, and minimizing toxicity. The review also addresses clinical implications and future directions in personalized medicine and pharmacokinetic modeling.