Abstract:
The landscape of drug delivery has undergone a transformative evolution, driven by the pursuit of enhanced therapeutic efficacy, minimized side effects, and improved patient compliance. This review explores recent advances in the engineering of controlled and targeted drug delivery systems, highlighting how these innovations are reshaping modern therapeutics. We examine a wide range of delivery platforms—including nanoparticles, liposomes, micelles, hydrogels, dendrimers, and implantable devices—with an emphasis on design strategies that enable spatiotemporal control of drug release and site-specific targeting. Mechanisms such as pH-sensitive, temperature-responsive, enzyme-triggered, and ligand-mediated delivery are discussed in the context of disease-specific applications, particularly in oncology, neurology, and infectious diseases. Emerging trends such as stimuli-responsive systems, biomimetic carriers, and integration with diagnostic technologies (theranostics) are also considered. While significant progress has been made, challenges remain in scalability, regulatory approval, and clinical translation. This review underscores the critical role of interdisciplinary approaches in engineering precision drug delivery systems that are safer, smarter, and more effective.

Keywords: Controlled drug delivery, Targeted drug delivery, Nanoparticles, Liposomes, Drug release mechanisms.