Niosome

A niosome is a non-ionic surfactant-based liposome. Niosomes are formed mostly by cholesterol incorporation as an excipient. Other excipients can also be used. Niosomes have more penetrating capability than the previous preparations of emulsions.^[1] They are structurally similar to liposomes in having a bilayer, however, the materials used to prepare niosomes make them more stable and thus niosomes offer many more advantages over liposomes.

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.^[2]

Methods of preparation

Niosomes can be prepared by various methods, including:

• ether injection method
• hand shaking method
• reverse phase evaporation technique
• trans membrane pH gradient
• the "Bubble" method
• formation of niosomes from proniosomes^[3]

Applications

Niosomes are a novel drug delivery system that are finding application in:

• drug targeting
• antineoplastic treatment
• leishmaniasis treatment
• delivery of peptide drugs
• studying immune response
• carriers for haemoglobin
• transdermal drug delivery systems^[4]
• cosmetics^[5]

References

1. ^ Your Source of Information: Niosomes
2. ^ PharmaXChange.info - Niosomes Article on niosomes covering topics such as structure, methods of preparation, advantages and applications
3. ^ PharmaXChange.info - Niosomes
4. ^ - Niosomes
5. ^ http://www.freepatentsonline.com/4830857.html