Nose to brain delivery of drugs for CNS diseases

Abstract

The management of central nervous system diseases is extremely challenging due to the numerous obstacles that stand against the successful delivery of drugs to their target site in the brain. Defeating the blood-brain barrier is considered the most significant challenge in this delivery. Different alternative routes of administration have been investigated. Nasal delivery is one of the possible ways for direct brain targeting. The nasal mucosa is the only part of the body at which the external environment become in straight connection with the central nervous system which takes place through the olfactory portion of the nasal mucosa. Different mechanisms have been suggested to describe the pathway for straight nasal to brain transport of medications, however, the precise route is still vague. The most important proposed pathways include nerve pathways (olfactory and trigeminal nerve), vascular, lymphatic, and cerebrospinal fluid mediated pathways. Among these mechanisms, the olfactory intra-neuronal delivery is the dominant one. Various particulate systems have been investigated for nasal delivery with the intention of direct transport to the brain. The most frequently studied delivery systems are polymeric nanosystems, lipid based nanosystems, and nanometric emulsions. In conclusion, direct nasal-to-brain delivery is a very fertile research area and any achievements in this area are running side by side with the progressions that occur in the particulate systems.

Promising brain biodistribution of insulin via intranasal dry powder for nose-to-brain delivery

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Nasal In-situ Gel of Inert Cellulose for Allergic Rhinitis

“…It forms a blanket over the nasal mucosa that, together with the cilliary action of the epithelial layer, act to " wash out" any foreign substance entering the nose posteriorly to the nasopharynx where they can be swallowed or expectorated. 10 For any material to act as a barrier against allergen contact, it has to stay on the mucosa for a while, and to resist the continuous washing effect of the beating cilia. 4 Indeed, in addition to barrier action of this nasal application, there is increasing consideration to nasal route utilization for immunization.…”