Vesicles from polysorbate 20 and cholesterol - A simple preparation and a characterization

A simple and rapid preparation of non-ionic surfactant vesicles is reported. These vesicles were obtained by sonication of appropriate mixtures of polyoxyethylene sorbitan-monolaurate (Tween 20) and cholesterol. The effect of the Tween 20/cholesterol ratio on the overall yield of non-ionic surfactant vesicles and on vesicle dimension and stability at different temperatures was investigated. Electron micrographs and fluorescence anistropy measurements showed that the obtained vesicles have a bilayer structure similar to that of liposomes. Non-ionic surfactant vesicles loaded with hydrophilic and lipophilic model molecules showed entrapment efficiency values comparable to those of phospholipid small unilamellar vesicles.