Any drug given in the form of parenteral dosage form like emulsion, suspension, solution etc. it is not best suited for the long time therapy. Long time drug release profile in controlled manner achieved by nano particle which is difficult by parenteral suspension or parenteral solution. Nano particulate drug delivery is the novel concept now a days. Nano particulate drug delivery is used to get maximum bio-availability for the potent drug with minimal side effect. Nano particulate drug delivery is also useful for maintaining the drug concentration in therapeutic window for the drug having narrow therapeutic window. Nano particulate drug delivery having disadvantage like cost effective even though it is widely useful because of its ease of preparation and suitability with most of drugs and excipients.