Nano-emulsion based formulations overcoming blood brain barrier for CNS disorders Central nervous system related disease treatment is usually cumbersome owing to incapability of the medications to escape the blood brain barrier, blood-CSF barrier, and effluxtransporters. so regular treatments have been largely replaced by the advanced nano technological procedures such as nano-emulsion via different administration routes. And among them intranasal route is used most commonly. As it is the non-invasive way to transport the medicine directly to the CNS. Here are some of the Nanoemulsion based formulations being used to treat neurodegenerative ailments.? The levels of TNF? responsible for neuroinflammatory signalling that aggravates the pathological process for conditions ( like Huntington’s disease, epilepsy, Alzheimer’s disease, Parkinson’s disease and others) has been decreased by the use of siRNA in contrary to TNF?, in a cationic nanoemulsion of omega-3 fatty acids containing flaxseed oil, by the intranasal administration . In the formulation DOTAP lipid is used because of its cationic nature that facilitates higher exposure by increased mucosal residence duration, increased loading capacity and complexation with the negatively charged biomolecules, for enhanced intracellular transport. Particle size for the nanoemulsion is <400nm that provide increased surface area for absorption and interaction in olfactoryepithelium.? HIV virus has the ability to reside inside the CNS that made the currently available anti-HIV drugs less effective. As they are not able to cross the blood brain barrier due to their less permeability so cannot completely remove the pathogen from body.cns distribution and oral bioavailability of the protease inhibitor squanavir is increased by the nanoemulsion formulation containing polyunsaturated fatty acids (PUFA) as the internal oil phase and the external consist of mixture of lipoid-80 and deoxycholic acid. Particle size of the oil droplets is in 100-200nm range. Reduced particle size and lipophilic nature enhanced permeability across the barrier and solved the problem. ?