Cholesterol‐containing phosphatidylcholine liposomes: Characterization and use as dispersed phase in electrokinetic capillary chromatography

Unilamellar liposomes were investigated by capillary electrophoresis, light scattering, and monolayer penetration techniques. Zwitterionic liposomes with and without cholesterol were compared and the effects of pH (7.40 and 8.25) and buffer (various sulfonic acid buffers, Tricine, and phosphate) on the electrophoretic mobilities and sizes of the liposomes were studied. Anionic liposomes containing phosphatidylserine with and without various amounts of cholesterol were used as dispersed phase in electrokinetic capillary chromatography in the separation of six steroidal hormones, with a focus on selectivity differences with increasing amounts of cholesterol in the liposomes. The results were confirmed by monolayer penetration measurements.