A 40% of the new drug candidates under FDA review. Considerable efforts have been directed at increasing the solubility of these hydrophobic compounds by creating nanoparticles formulations with high surface- to-volume ratios. Conventional techniques to form Nanoparticles include slow anti-solvent addition followed by dialysis, solvent evaporation and emulsification followed by solvent stripping. Rapid precipitation from an organic solvent into an aqueous anti-solvent has proven an attractive processing scheme for laboratory studies as well as for large scale operations. Nanoparticles are solid colloidal particles composed of natural, synthetic, or semi synthetic polymers. The size ranges from 1 nm to 1000 nm. The drugs or other molecules may be dissolved into the nanoparticles, entrapped, encapsulated, and/or adsorbed or attached.A variety of drugs such as hydrophilic drugs, hydrophobic drugs, proteins, vaccines, and biological macromolecules using nanoparticles as carriers. Nanoparticles have a further advantage over larger microparticles, because they are better suited for intravenous delivery.Nanoparticles have been highly exploited for controlled drug release.