Various Techniques for Preparation of Nanosuspension- A Review
Many of the newly developed drugs are poorly soluble and they create major problems during formulation and shows poor bioavailability. The problem is even more complex for drugs which belong to BCS Class II category. To overcome these problems nanotechnology is used to improve the solubility as well as bioavailability of poorly soluble drugs. Nanotechnology is defined as the science and engineering carried out in the nanoscale that is 10-9 meters. Nanosuspensions are a part of Nanotechnology. Nanosuspensions are defined as the submicron 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 differ from nanoparticles and solid lipid nanoparticles with respect to the fact that nanoparticles are polymeric colloidal carriers of drug while solid lipid nanoparticles are lipid carrier of drugs. Preparation of nanosuspension is simple and applicable to all drugs which are water insoluble. Nanosuspensions are prepared by using wet mill, high pressure homogenizer, emulsion solvent evaporation, melt emulsification and supercritical fluid techniques. Nano-suspensions can be delivered by oral, parenteral, pulmonary and ocular routes. Nanosuspensions can also be used for targeted drug delivery when incorporated in the ocular inserts and mucoadhe-sive hydrogels. This review article mainly focuses on preparation of nanosuspensions by various techniques with their advantages and disadvantages, formulation considerations, Characterization and their applications in drug delivery. Nanosupensions not only solves the problem of poor solubility and bioavailability but also alter the pharmacokinetics of the drug and thus improving safety and efficacy.