ABSTRACT:
This review aims to evaluate the evidence for the existence of a direct nose to brain delivery. Blood brain barrier (BBB) represents one of the strictest barriers for delivery of drugs to brain due to restricted exchange of hydrophilic compounds, proteins between plasma and central nervous system (CNS). From last few years due to restricted entry of many therapeutic agents to CNS, the diseases of CNS like Alzheimer’s, parkinsonism, brain tumors, anxiety, neuronal disorders, depression etc. can’t be treated efficiently. Different attempts were made for CNS drug delivery, but the fraction of drug reach to brain is too less due to BBB. Intranasal brain targeting is a new attempt for CNS delivery which bypasses the BBB and increases the fraction of drug reaches to CNS. This is because of direct contact of olfactory and trigeminal nerves with CNS. Here olfactory epithelium acts as channel for drug entering to brain. This pathway is novel, simple and non-invasive approach which eliminates the need for systemic delivery and unwanted systemic side effects. A wide variety of therapeutic agents without any modification can be delivered to brain by this route. Therefore present study critically tries to evaluate the evidence of nasal-brain transport with a focus on drug carriers, transport pathways, formulation aspects and to suggest future strategies that may contributes in the field of nasal brain drug delivery.