Niosome

A niosome is a non-ionic surfactant-based vesicle. Niosomes are formed mostly by non-ionic surfactant and cholesterol incorporation as an excipient. Other excipients can also be used. Niosomes have more penetrating capability than the previous preparations of emulsions. They are structurally similar to liposomes in having a bilayer, however, the materials used to prepare niosomes make them more stable. It can entrap both hydrophilic and lipophilic drugs, either in an aqueous layer or in a vesicular membrane made of lipid material.
Structure.
Niosomes are lamellar structures that are microscopic in size. They constitute of non-ionic surfactant of the alkyl or dialkyl polyglycerol ether class and cholesterol with subsequent hydration in aqueous media. The surfactant molecules tend to orient themselves in such a way that the hydrophilic ends of the non-ionic surfactant point outwards, while the hydrophobic ends face each other to form the bilayer. The figure in this article on niosomes gives a better idea of the lamellar orientation of the surfactant molecules.
Methods of preparation.
Niosomes can be prepared by various methods, including:
Applications.
Niosomes are a novel drug delivery system that are finding application in: