All liposome samples were purified by size exclusion chromatography using PD Minitrap™ G-25 separation columns to separate the surrounding hydration solution from the liposomes themselves. In this way, 1 ml of purified liposome solution was collected. The principle of CF release kinetics measurement is based on the fluorescence quenching of concentrated CF. The intraliposomal CF does not fluoresce; its fluorescence increases sharply only upon dilution after release from the liposomes. For this reason, the hydration medium had to be separated from the liposomes before conducting any permeation experiments.