Smart Drug Delivery System: An Intelligent Approach Toward Precision Drug Delivery: A Review

Smart drug delivery systems (SDDS) have attracted growing interest in pharmaceutical research because they offer new ways of carrying drugs to, and releasing them at, the intended site in the body. Unlike conventional dosage forms, these systems can be engineered to respond to conditions inside the body or to externally applied triggers, including changes in pH, redox potential, enzyme activity, temperature, light, magnetic fields, ultrasound, and glucose concentration. This review outlines the principles behind SDDS, the main carrier platforms used to build them, their therapeutic applications, and the obstacles that limit wider clinical use. The platforms covered are liposomes, polymeric nanoparticles, exosomes, hydrogels, dendrimers, microneedles, and polymeric micelles; for each, the key properties and drug-release behavior are discussed. Applications in cancer, infections, diabetes, and inflammatory disease are also considered. Despite their advantages, SDDS still face substantial challenges: biological barriers, toxicity to healthy cells, insufficient accumulation at the target site, unstable formulations, difficulty in reproducible manufacturing, and unresolved regulatory questions. If these obstacles can be overcome, SDDS holds considerable promise for improving how drugs are delivered.