Pharmaceutical nanotechnology has revolutionized drug delivery by enabling precise control over drug release kinetics, biodistribution, and therapeutic outcomes. Conventional drug formulations often suffer from poor bioavailability, non-specific distribution, rapid clearance, and systemic toxicity, necessitating the development of advanced nanocarrier systems. This review examines emerging trends in pharmaceutical nanotechnology focused on controlled, targeted, and sustained drug release applications. Key nanocarrier platforms including polymeric nanoparticles, liposomes, solid lipid nanoparticles, dendrimers, micelles, and inorganic nanocarriers are critically evaluated for their physicochemical properties, drug loading mechanisms, and release kinetics. The mechanistic principles governing controlled drug release—including diffusion-mediated, erosion-controlled, and stimuli-responsive mechanisms—are systematically analyzed alongside passive and active targeting strategies that exploit enhanced permeability and retention effects, ligand-receptor interactions, and environmental triggers. Therapeutic applications in oncology, infectious diseases, chronic inflammatory conditions, and neurological disorders demonstrate the translational potential of these systems. Despite significant advances, formulation complexity, scalability challenges, regulatory uncertainties, and immunological concerns remain critical barriers to clinical translation. Future developments in personalized nanomedicine, artificial intelligence-guided design, and regulatory harmonization are expected to accelerate the clinical adoption of pharmaceutical nanotechnology. This comprehensive review provides pharmaceutical scientists and clinicians with mechanistic understanding and practical insights into the design, optimization, and therapeutic implementation of next-generation nanocarrier-based drug delivery systems.