Niosomes: an Excellent Tool for Drug Delivery

Design and development of novel drug delivery system (NDDS) has two prerequisites. First, it should deliver the drug in accordance with a predetermined rate and second it should release therapeutically effective amount of drug at the site of action. Conventional dosage forms are unable to meet these requisites. Niosomes are essentially non-ionic surfactant-based multilamellar or unilamellar vesicles in which an aqueous solution of solute is entirely enclosed by a membrane resulting from the organisation of surfactant macromolecules as bilayer. Niosomes are formed on hydration of non-ionic surfactant film which eventually hydrates imbibing or encapsulating the hydrating aqueous solution. The proposed review deals with composition, methods of preparation, and applications of niosomes in the pharmaceutical field. The main aim of development of niosomes is to control the release of drug in a sustained way, modification of distribution profile of drug and for targeting the drug to the specific body site. IJRPC 2012, 2(2) Nasir et al ISSN: 22312781 480 9. The surfactants are biodegradable, biocompatible and non-immunogenic. NIOSOME FORMATION Theoretically, niosomal formation requires the presence of a particular amphiphile and aqueous solvent. The association of amphiphile monomers into vesicles on hydration is the result of a high interfacial tension between water and hydrocarbon portion (or any other hydrophobic group) of the amphiphile, causing them to associate. Simultaneously, the steric hydrophilic and ionic repulsion between the head groups ensure that these groups are in contact with water. These two opposite forces lead to a supramolecular assembly. The essential components in the preparation of niosomes are membrane additives such as cholesterol and non-ionic surfactants.