Intranasal Nano-Delivery Systems: Emerging Strategies for Central Nervous System Disease Therapeutics

The rising global incidence of central nervous system (CNS) diseases, exacerbated by the formidable blood-brain barrier (BBB) hindering effective drug delivery, necessitates novel therapeutic strategies. Nasal administration has emerged as a promising non-invasive route, bypassing the BBB via direct neural pathways (olfactory/trigeminal), systemic absorption, or lymphatic drainage. However, inherent nasal barriers like the mucus layer and epithelium limit its efficacy. This review distinguishes itself by integrating mechanistic insights into nasal transport pathways with the rational design of advanced nano-delivery systems. We first outline the challenges in CNS drug delivery and detail the nasal anatomy and transport pathways facilitating nose-to-brain delivery. Subsequently, we emphasize the critical properties required of advanced nano-carriers to improve mucosal penetration, prolong retention, and promote drug accumulation at cerebral injury sites. Following a detailed analysis of the advantages and limitations associated with nose-to-brain delivery, we consolidate recent advances in nasal nano-delivery systems for treating CNS disorders, emphasizing their capacity to improve brain-targeting efficiency, enhance therapeutic efficacy, reduce systemic toxicity, and enable previously undruggable CNS targets. Finally, we expand the discussion to encompass current challenges impeding clinical translation, including safety concerns, manufacturing scalability, and regulatory hurdles, while highlighting emerging trends such as artificial intelligence-driven formulation design. This comprehensive analysis aims to deepen the understanding of nasal-to-brain transport mechanisms and inform the future development of effective nasal formulations for improved neurological therapeutics.