AN OVERVIEW ON EXPLORING NASAL MICROEMULSION FOR TREATMENT OF CNS DISORDERS

Nasal route is found to be valuable for targeting drugs to CNS via different mechanisms. The advantages, disadvantages, varius aspects of nasal anatomy and physiology, mechanism of drug transport from nose brain, drug selection criteria to cross BBB/Blood-CSF barrier are discussed briefly. The relevant aspects of physicochemical, formulation and physiological factors of nasal cavity that must be considered during the process of discovery and development of new drugs for nasal delivery drugs as well as in their incorporation into appropriate nasal pharmaceutical formulations are discussed here. There are various approaches in delivering a therapeutic substance to the target site in a controlled release fashion. One such approach is using microemulsion as carriers for drugs. Microemulsions are isotropic, thermodynamically stable transparent (or translucent) systems of oil, water and surfactant, frequently in combination with a cosurfactant with a droplet size usually in the range of 10-100 nm. They can be classified as oil-in-water (o/w), water-in-oil (w/o) or bicontinuous systems depending on their structure and are characterized by ultra-low interfacial tension between oil and water phases. Microemulsion received much attention not only for prolonged release, but also for targeting of drugs to a particular site. The intent of the paper is focuses on use of microemulsion technology in drug targeting to the brain along with mechanism of nose to brain transport, formulation and formation of microemulsion and its characterization.