Drug delivery plays an important role on its efficacy. Some drugs have an optimum concentration range with in which maximum benefit is derived and concentration above (or) below the range can be toxic or produce no therapeutic effect. On the other hand, the very slow progress in the efficacy of the treatment of severe diseases, has suggested a growing need for a multidisciplinary approach to the delivery of therapeutics to targets in tissues. The main goal for developing such delivery systems is to minimize drug degradation and loss, to prevent harmful side-effects and to increase drug bioavailability and the fraction of the drug accumulated in the required zone.Targeting is the ability to direct the drug loaded system to the site of interest. Two major mechanisms can be distinguished for addressing the desired sites for drug release; (a) active targeting and (b) passive targeting.Drug carrier systems such as micellar solutions, vesicle and liquid crystal dispersions, as well as nanoparticle dispersions consisting of small particles of 10?400 nm diameter show great promise as drug delivery systems.