Inhalable Nanocarriers for Pulmonary Drug Delivery Systems: A Comprehensive Review

Pulmonary drug delivery has emerged as a promising approach for the treatment of respiratory and systemic diseases due to the unique anatomical and physiological characteristics of the lungs, including a large surface area, extensive vascularization, and rapid drug absorption. However, conventional inhalation systems such as metered dose inhalers, dry powder inhalers, and nebulizers often suffer from limitations including poor lung deposition, rapid mucociliary clearance, low bioavailability, and reduced therapeutic efficiency. In recent years, inhalable nanocarriers have gained considerable attention as advanced pulmonary drug delivery platforms capable of overcoming these challenges. These nanosized systems, including liposomes, polymeric nanoparticles, solid lipid nanoparticles, nanostructured lipid carriers, dendrimers, micelles, and nanoemulsions, offer advantages such as enhanced lung retention, controlled drug release, improved mucus penetration, and targeted delivery. This review comprehensively discusses the anatomy and physiology of the respiratory tract, mechanisms of particle deposition, formulation strategies, and characterization techniques associated with inhalable nanocarriers. Furthermore, their therapeutic applications in asthma, chronic obstructive pulmonary disease, tuberculosis, lung cancer, cystic fibrosis, pulmonary fibrosis, and viral infections are highlighted. The review also addresses safety concerns, nanotoxicity, clinical translation, regulatory considerations, and emerging future perspectives including smart inhalers, personalized nanomedicine, and AI-assisted formulation development. Overall, inhalable nanocarriers represent a promising strategy for advancing next-generation pulmonary therapeutics.