Abstract
Vesicles composed of sorbitan monooleate (Span 80) were prepared by a two-step emulsification method. The water-in-oil (W/O) emulsions generated in the first step of emulsification exhibited a quite dynamic and large hydrophobic difference between water and hexane. A subsequent emulsification yielded the vesicles with a fluid and flexible interface, as compared with that of liposomes. It was furthermore demonstrated that the two-step emulsification method has the advantage of the introduction of a PEG layer into the outer surface of the vesicles, while retaining the membrane properties of the vesicles.
