ABSTRACT
Nanotechnology has become an outgrowing field in novel drug delivery system. It confers several merits overconventional formulations like increased solubility and bioavailability, targeted drug delivery and a decreaseddose of the drug. The selection of appropriate method for the preparation of nanoparticulate system depends on thephysicochemical characteristics of the drug to be loaded and polymer. This review has covered the most widelyacceptable preparation techniques for polymeric and lipidic nanoparticles including nanoprecipitation, milling,extrusion, supercritical fluid technology, salting out, gelation, sonication, high-pressure homogenization, and solventemulsification methods. Nanocarriers, the traditional nano-formulation drug delivery systems, encountered somemajor problems in process scale-up, reproducibility, and stability during storage. To circumvent these problems a newapproach has emerged which are “In situ or self-assembled nanoparticles drug delivery system.” Such approachescomprise experimentation with different types of polymers, surfactants or novel process in order to prepare a preconcentrate of drug formulation, which on entering into an aqueous medium (gastrointestinal fluid, blood) will formnanoparticles. The in situ nanoformulations can be the futuristic approach in nanocarriers to overcome the problemsassociated with the scale-up process and also minimize the cost of production. This review focuses on differentpreparation techniques for polymeric and lipidic nanocarriers preparation, in situ nanoformulation approaches andrelease characteristics of stimuli responsive nanoformulation