A REVIEW ON PARTICLE SIZE REDUCTION OF ACTIVE PHARMACEUTICAL INGREDIENTS (APIs) AND ITS IMPACT ON DRUG PERFORMANCE

Particle size is an important physical attribute of an active pharmaceutical ingredient (API), because it can influence dissolution, absorption, powder handling, formulation uniformity, and product stability. For many poorly water-soluble drugs, slow dissolution can limit the amount of drug available for absorption after oral administration. Reducing particle size increases the total surface area exposed to the dissolution medium and may therefore improve the rate of dissolution. Conventional micronization and advanced approaches such as wet media milling, high-pressure homogenization, precipitation, and nanocrystal technologies are used to achieve different particle-size ranges. This review discusses the scientific basis of particle-size reduction and its practical influence on drug performance. It distinguishes dissolution rate from equilibrium solubility and explains why faster dissolution does not always produce higher bioavailability. The review also considers possible disadvantages, including agglomeration, poor powder flow, electrostatic charging, changes in crystallinity, and physical instability. Common characterization tools—including laser diffraction, dynamic light scattering, microscopy, X-ray powder diffraction, differential scanning calorimetry, surface-area analysis, and dissolution testing—are described as complementary ways to evaluate the resulting material . The literature indicates that particle-size reduction can be valuable when dissolution is a meaningful limitation, but its success depends on the API, dosage form, process conditions, and physiological environment. A rational development strategy should therefore select a suitable size range rather than simply pursue the smallest possible particles. Particle size should be assessed alongside solid-state properties, wettability, stability, manufacturability, and relevant biopharmaceutical evidence.