Polymeric Micelles: A Review of Their Synthesis, Characterization, Types & Applications

A significant proportion of new drug candidates suffer from poor water solubility, posing challenges in their development and effective delivery, particularly via parenteral routes. Polymeric micelles, composed of amphiphilic block or graft copolymers, have emerged as promising nanocarriers to overcome this limitation. These micelles possess a core-shell structure, where the hydrophobic core encapsulates poorly soluble drugs and the hydrophilic shell ensures colloidal stability and prolonged circulation. The self-assembling nature of these carriers enables enhanced solubility, improved drug loading, reduced toxicity, and site-specific targeting, especially to tumors via the Enhanced Permeability and Retention (EPR) effect. Preparation techniques such as dialysis, solvent evaporation, freeze-drying, and oil/water emulsification offer flexibility for incorporating a wide range of drugs. Critical characterization parameters include size, shape, critical micelle concentration (CMC), stability, and drug release behavior. Additionally, functionalization of micelles enables stimuli-responsive behavior such as pH-sensitivity, enabling controlled drug release in acidic tumor environments. Several polymeric micelle formulations have advanced to clinical trials, highlighting their clinical relevance. Their nanoscale size, biocompatibility, and structural adaptability make polymeric micelles a versatile platform for delivering hydrophobic drugs, macromolecules, and genes. This review outlines their synthesis, properties, advantages, and therapeutic applications in modern drug delivery systems.