Research progress in brain-targeted nasal drug delivery: physiological pathways, key absorption factors, biomaterial-based improvements, and CNS applications

Brain-targeted nasal drug delivery uses the anatomical connection between the nasal cavity and the brain to help drugs bypass the blood-brain barrier via intranasal administration. The review highlights why nasal dosing can be advantageous compared with oral and injection routes, including bypassing first-pass metabolism and reducing poor injection compliance, while aiming for higher brain activity at lower doses to limit adverse effects. It summarizes key drug entry pathways (from the nasal mucosa to brain targets), major factors that influence absorption and bioavailability (including formulation and delivery enhancers), and common experimental approaches used in intranasal research. The paper also discusses how biomaterials can improve nasal mucosal delivery systems and reviews current limitations, positioning intranasal brain-targeted delivery as a promising strategy for preventing and treating central nervous system diseases.