Nose to Brain Drug Delivery: A Novel Approach Through Solid Lipid Nanoparticles

Certain mechanism like presence of highly complex structure i.e. blood brain barrier (BBB), P-glycoprotein (active efflux transporter) and certain enzymatic activity protect the brain in adverse conditions. These mechanisms especially BBB frustrate therapeutic interventions during the treatment. As a result most of the drug substances are fruitless in treating brain disorders, because they are not able to reach the brain in desired amount required for therapeutic activity. As a consequence, several invasive and non-invasive strategies are presently being used to increase the delivery of drugs across the BBB by opening it. However, opening the BBB by such strategies may allow the entry of certain undesirable substances to the brain and may cause the damage. There are several drugs (especially peptides and proteins) which cannot cross the BBB or produce the systemic side effects when given orally. Due to the potential problems, an attempt has been made to conquer the barrier issues in-vivo by using a noninvasive approach i.e. intranasal drug deliver using solid lipid nanoparticles (SLNs). It is an innovative, practically feasible and simple approach for delivery of certain categories of drug that cannot reach the brain due to above mentioned reasons. The drug administered through intranasal route bypasses the BBB and prevents the systemic exposure of drug and hence systemic side effects associated with drug molecules. This is due to the unique connection provided by olfactory and trigeminal nerves between the brain and external environment. SLNs are lipid nanoparticles made up of solid lipids, possessing exclusive benefits over other drug delivery carriers. The lipids used for the preparation of SLNs are usually biocompatible. They can be used as drug carrier to overcome the BBB when administered through nose. The article aims to discuss the various barriers to CNS drug delivery, strategies to overcome the BBB, anatomy and physiology of nose, SLNs & their characteristic parameters and applications of SLNs in brain delivery.