Polymeric Nanocarriers in Drug Delivery

Pharmacotherapy has shifted significantly from traditional drug delivery systems to precision nanomedicine. Polymeric nanocarriers, including nanospheres, nanocapsules, polymeric micelles, dendrimers, polymersomes, and nanogels, have now become multipurpose carriers to address key limitations: low solubility, early systemic clearance, and nonselective toxicity. This review is a critical and detailed study of the most recent developments in polymeric nanocarrier systems, focusing on their structural differentiation, physicochemical properties, and biological activity. Natural and synthetic polymers are both tested for biodegradability, biocompatibility, and functionality adaptation. Modern methods of fabrication, including solvent-based nanoprecipitation and controlled synthesis of dendrimers, are scrutinized critically in relation to the scaling up and translation issues to industry. The systematically analyzed aspects of drug delivery include the passive delivery using the Enhanced Permeability and Retention (EPR) effect, active delivery using the ligand-mediated method, and stimuli-responsive release. Moreover, this review highlights other emerging trends, including multifunctional hybrid nanostructures, green synthesis, nanotoxicological and regulatory considerations, and clinical translocation. Clinical advancements and approved formulations by the FDA have also been provided in recent times. Lastly, future directions are also provided in the integration of Artificial Intelligence (AI) into the formulation design and the shift to personalized nanomedicine. In general, this review gives the future outlook of polymeric nanocarriers as the nextgeneration drug delivery systems.