Intranasal nanoemulsion for targeted medication delivery to the brain: a novel approach to treat psychotic disorder.

The brain is one of the most delicate & protected organs of the human body. The circulation of blood to the brain is secured by the blood-brain barrier (BBB), blood-cerebrospinal fluid barrier (BCSFB), and cerebrospinal fluid-brain barrier (CBB). These barriers also restrict the distribution of therapeutics to the central nervous system (CNS) for the treatment of any psychotic disorder. Oral & parenteral routes are the main routes for the delivery of anti-psychotics to the brain. Still, associated drawbacks include the stomach's acidic pH, first-pass metabolism, enzymatic degradation, plasma protein binding and finally, the barriers of brain. One of the novel routes for directly targeting the drug to the brain is the intranasal route, which bypasses the BBB. The drug is delivered to the brain via the olfactory & trigeminal nerve regions located in the septum & ceiling of the nasal cavity, reaching the brain more quickly and at higher concentrations than viat the systemic circulation or other tissues. In most cases, nasal doses are 2-10 times less than the oral dose. Nanoemulsions (NE) are bi-phasic dosage forms of two immiscible liquids stabilized by surfactants having a mean droplet size of 100-300 nm. NE is attracting increasing interest in nose-to-brain delivery (N2B) due to its ability to address issues related to drug solubility & drug stability. The smaller droplet size of NE provides a larger surface area, thereby increasing the dissolution rate according to the Noyes-Whitney equation.