Many of the recently developed new chemical entities are poorly water soluble and they create major problems during formulation and development of new dosage form and shows poor bioavailability. The drugs belong to BCS class II has problem of solubility, to overcome the solubility problem nanotechnology is most useful technique. Nanosuspensions are defined as the submicron biphasic colloidal dispersions of pharmaceutical active ingredient particles in a liquid phase, size below 1μm, without any matrix material which are stabilized by surfactants and polymers. Nanosuspensions are nanoparticles being composed of 100% drug without any matrix material. In this review the main focus is given on various techniques conventional as well as patented technology used for preparation of nanocrystals. There are certain characterization paratemeters such as particle size, polydispersibility index, surface morphology, particle surface charge, crystalline state, Surface hydrophilicity, Adhesion properties for the nanocrystals formulation. This is suitable drug delivery system for all commonly used routes of administration such as oral, IV, SC, and IM and topical application. In addition, nanocrystals can be incorporated into the tablets, capsules, fast-melts and lyophilized for sterile product applications.
