Niosomes: A Vesicular Drug Delivery System

Abstract

Niosomes or Non ionic surfactant vesicles are microscopic lamellar structures formed on admixture of non ionic surfactant of the alkyl or dialkylpolyglycerol ether class and cholesterol with subsequent hydration in aqueous media. Niosomes are unilamellar or multi lamellar structures that are microscopic in size. They are vesicular systems similar to liposomes that can be used as carriers of amphiphilic and lipophilic drugs[1]. The basic process of preparation is hydration by aqueous phase of the lipid phase which may be either a pure surfactant or a mixture of surfactant with cholesterol. Later preparing niosomal dispersion, by dialysis centrifugation or gel filtration the un entrapped drug is separated. The use of dialysis tubing is also included in Invitro rate release. Niosomes have been widely evaluated for controlled release and targeted delivery for treatment of cancer, viral infections and other microbial diseases. Circulation of the entrapped drug in body prolong as niosomes can entrap both hydrophilic and lipophilic drugs. Stable noisome dispersion must exhibit a constant particle size and a constant level of entrapped drug. Niosomes also serve better aid in diagnostic imaging and as a vaccine adjuvant. Niosomes are promising vehicle for drug delivery and being non ionic, it is less toxic and improves the therapeutic index of drug by restricting its action to target cells. They have all the advantages of liposomes but their low cost, greater stability and resultant ease of storage has lead to the exploitation of non ionic surfactants as alternative to phospholipids. This article gives information about the advantages, disadvantages, preparation methods, factors affecting, characterization, Invitro methods, and niosomal applications.[2]