Niosomes: a Role in Targeted Drug Delivery System

Niosomes are non-ionic surfactant vesicles inclosing an aqueous phase and a wide range of molecules could be encapsulated within aqueous spaces of lipid membrane vesicles. They are microscopic lamellar structures formed on the admixture of a non-ionic surfactant, cholesterol and phosphate with subsequent hydration in aqueous media. Niosomes belongs to novel drug delivery system which offers a large number of advantages over other conventional and vesicular delivery systems. Namely they are the targeted drug delivery system which showing reduction of dose, stability and compatibility of non-ionic surfactants, easy modification, delayed clearance, suitability for a wide range of Active Pharmaceutical Agents. INTRODUCTION: The basic goal of the drug therapy is to achieve a steady state blood or tissue level that is therapeutically effective and nontoxic for an extended period. The design of proper dosage regimen was an important element in accomplishing the goal. Novel drug delivery systems are aiming to delivery the drug at a rate directed by the needs of the body during the period of treatment and channel the active entity to the site of action. Targeted drug delivery implied for selective and effective localization of pharmacologically active moiety at pre-identified (preselected) targeted in therapeutic concentration while restricting its access to non-target normal cellular linings thus it minimizing the toxic effect and maximizing therapeutic index. Targeted drug delivery was an event where a drug carrier complex/conjugate delivers drug (s) exclusively to the pre-identified targeted cells in a specific manner. To pursue the optical drug action, functional molecules could be transported by a carrier to the site of action and released for performing their task. The targeting methods may be classified as chemical methods, by covalent bonding and physical methods. Chemical methods involved chemical modification of the parent compound to a derivative, which was activated only at the target site. Various physical methods made use of the carriers such as liposomes, niosomes, resealed erythrocytes, platelets, magnetic microspheres, nanoparticles, and monoclonal antibodies. Recently the niosomal drug delivery system (A particulate colloidal carrier system) is basically drawing attention due to its significant advantages over conventional drug delivery system. Niosomes are the nonionic surfactant vesicles with lamellar structure which may be unilamellar and multilamellar serve to be efficient in providing the required advantages like: to develop the effective delivery system to achieve maximum effective concentration, to form vesicles that able of entrapping hydrophilic and hydrophobic molecules, modification of the particle composition or surface could adjusted the affinity for the target site and/or the drug release