Liposomes as carriers in electrokinetic capillary chromatography

Liposomes are small membrane-enclosed vesicles composed of either natural o r synthetic lipids. Their size can be adjusted on a wide scale and they can be made with well-defined compositions. While liposomes have been extensiv ely used as model biomembranes they have also gained a considerable degree of attention as carriers for drugs as well as for genetic material. The phy sical properties of liposomes are critically dependent on their chemical co mposition. In this study liposomes were applied as pseudostationary phases in electrokinetic capillary chromatography. Various negatively charged lipo somes, consisting of mixtures of zwitterionic and anionic lipids, were inve stigated. Major emphasis was put on clarifying the effects of the total lip id concentration, the lipid molar ratio, the lipid bead group, and the buff er on the capillary electrophoretic separation of neutral analytes. In addi tion, the influence of the physical state of the membrane, i.e., gel vs, fl uid, on the separation was investigated. Corticosteroids were applied as mo del analytes.