From Nose to Brain: Unlocking Nasal Delivery to Reduce Pill Burden in Neuroprotective Therapies

Neurodegenerative and neurological diseases represent a significant and growing global health burden, which is largely due to the demographic (population age) and lack of disease-modifying treatment. The traditional oral neuroprotective drugs are often limited by the low permeability of the blood-brain barrier, first-pass metabolism, systemic side effects, and polypharmacy and pill burden, especially in the geriatric population. These shortcomings underscore the necessity of different, patient-friendly methods of drug delivery, which may be used to promote central nervous system targeting with reduced systemic exposure. Nose-to-brain intranasal delivery has become an encouraging non-invasive method that permits direct delivery of therapeutic agents into the brain by taking olfactory and trigeminal neural routes, avoiding the blood-brain barrier. This is a critical review on the anatomical and physiological basis of nasal drug delivery, the mechanism behind neuronal and extra-cellular delivery as well as more advanced formulation technology such as mucoadhesive system, in situ gel and nanotechnology based carriers. Its use in significant neurological diseases, such as Alzheimer disease, brain tumors, Multiple sclerosis, Parkinson disease, epilepsy, stroke, and epilepsy, is also discussed as a basis of translational relevance. There are also contemporary issues of mucocillar clearance, dosing volume, enzyme degradation and control that are discussed. Together, intranasal delivery is a disruptive approach that can help decrease the pill burden, increase adherence to patients, and increase targeted therapy in neuroprotection. Further interdisciplinary studies and clinical confirmation are necessary to fully achieve its effect in modern CNS pharmacotherapy.