ABSTRACT
I. INTRODUCTION Niosomes are vesicles mainly consisting of nonionic surfactants. This class of vesicles was introduced by Handjani-Vila et al. (1) in 1979. One of the reasons for preparing niosomes is the assumed higher chemical stability of the surfactants than that of phospholipids, which are used in the preparation of liposomes. Due to the presence of ester bonds, phospholipids are easily hydrolyzed (2). This can lead to phosphoryl migration at low pH. Another type of degradation is the peroxidation of unsaturated phospholipids (3). In order to avoid peroxidation processes, vesicles are often stored under nitrogen atmosphere. Unreliable reproducibility arising from the use of lecithins in liposomes leads to additional problems and has led scientists to search for vesicles prepared from other material, such as nonionic surfactants.
