A Nanosuspension is a submicron colloidal dispersion of drug particles. A pharmaceutical nanosuspension is defined as very finely colloid, Biphasic, dispersed, solid drug particles in an aqeous vehicle , size below 1µm ,without any matrix material, stabilized by surfactants and polymers , prepared by suitable methods for Drug Delivery applications, through various routes of administration like oral ,topical ,parenteral ,ocular and pulmanary routes.