Smart Polymers in Controlled Drug Release: Mechanisms and Clinical Applications

Smart polymers, also referred to as stimuli-responsive polymers, represent a transformative class of materials in the field of drug delivery. These polymers have the unique ability to undergo reversible or irreversible physical and chemical changes in response to external or internal stimuli such as pH, temperature, light, enzymes, and redox conditions. Their adaptability enables precise temporal and spatial control over drug release, which is especially advantageous in targeting diseased tissues while minimizing systemic side effects.Controlled drug delivery systems based on smart polymers offer significant improvements over conventional approaches by enhancing bioavailability, prolonging circulation time, and providing site-specific action. Recent advances in polymer synthesis, nanotechnology, and biomedical engineering have led to the development of sophisticated delivery platforms such as hydrogels, micelles, dendrimers, and nanogels that respond to biological uses.This review discusses the classification, mechanisms of action, and architectural diversity of smart polymers, as well as their clinical applications in oncology, diabetes, infection control, and neurological diseases. Current challenges and future perspectives in clinical translation and regulatory approval are also addressed, highlighting the potential of smart polymers to revolutionize personalized drug delivery strategies.