STRUCTURAL PROPERTIES OF NIOSOMAL VESICLES

Abstract

Targeting is a phenomenon in which the distribution of a drug in the body happens in
such a way that its main part interacts with the targeted tissue at the cellular or subcellular
level to achieve the desired pharmacological effect at a selected locus without unwanted
interactions in other organs. This can be achieved by using a drug delivery system such as
niosomes. They are vesicles (50–800 nm) consisting of a double layer of a nonionic
surfactant, often additionally containing cholesterol or its derivatives. The structure of
niosomes makes it possible to encapsulate both hydrophilic and lipophilic compounds in
them, while the hydrophilic agent is located in the internal water space, and the lipophilic
agent is located in the bilayer. The properties of these vesicles can vary depending on size,
lamellarity and surface charge. As a delivery system, niosomes have some advantages over
classical liposomes: they have a longer half lifetime, they are easy to obtain and can be easily
modified, highly compatible with biological systems and have low toxicity due to their
nonionic nature, they are non-immunogenic and are biodegradable. What is more, niosomes
are hardly recognized by the reticuloendothelial system. Niosomes are promising drug
delivery vehicles. They are considered as a method of targeted delivery of an active substance
and the possibility of controlled drug-release in the treatment of oncology, autoimmune
diseases, viral and other infectious diseases. The encapsulation of a drug in the vesicular
system prolongs its presence in the general circulation and increases the possibility of
penetration into the targeted tissue, reduces toxicity.