ABSTRACT
Lipid based nano drug delivery systems have gained momentum over the decades due to their role in improving bioavailability, controlling and targeting actives, enhancing stability and also as vaccine adjuvants. Nanostructured lipid carriers (NLCs) are mixtures of solid lipids with spatially incompatible liquid lipids. Oil-in-water or water-in-oil microemulsions can be phase-inverted by changing the temperature. Phase inversion can also be obtained with surfactants which are polyoxyethylated. High pressure homogenization is the preferred method as it avoids use of organic solvents commonly used during preparation. Spray drying is a cost effective technique than the lyophilization. The hydrophobic nature of essential oils aids their antimicrobial activity and can be used as an active in lotions, creams, ointments, emulsions for dermal applications. Poor stability of drugs in liquid lipids due to oxidative impurities, free fatty acids, coloring matters have been an inhibition for use of liquid lipids in NLC preparation. Lipid nanoparticles offer superior drug delivery over polymeric nanoparticles.
