Abstract

Nanotechnology-based drug delivery systems have emerged as a transformative paradigm in modern pharmacotherapy, offering fundamental solutions to the inherent limitations of conventional drug formulations including poor bioavailability, non-specific biodistribution, systemic toxicity, and inadequate therapeutic indices. This review provides a comprehensive and critical examination of the current landscape of nanocarrier technologies, encompassing polymeric nanoparticles, lipid-based vesicles, inorganic nanostructures, dendrimers, and emerging hybrid platforms. Particular emphasis is placed on mechanistic advancements in passive targeting via the enhanced permeability and retention effect, active targeting through ligand-receptor interactions, and stimuli-responsive release mechanisms triggered by endogenous microenvironments or exogenous physical stimuli. The translational trajectory of these systems is evaluated through their therapeutic applications in oncology, infectious diseases, and chronic disorders, with critical analysis of approved formulations and candidates in clinical development. Despite substantial preclinical success, persistent challenges including nanotoxicity, immunogenicity, manufacturing scalability, regulatory heterogeneity, and cost-effectiveness continue to impede widespread clinical adoption. This review synthesizes recent evidence regarding these barriers and proposes strategic frameworks for their mitigation. Future perspectives emphasize the convergence of personalized nanomedicine with artificial intelligence-driven predictive modeling, the evolution of smart multifunctional nanocarriers capable of theranostic integration, and the development of biomimetic systems that leverage endogenous biological mechanisms. Collectively, nanotechnology-based drug delivery platforms represent not merely an incremental improvement but a fundamental reconceptualization of pharmaceutical intervention, with the potential to enable previously unattainable therapeutic strategies.