Determination of Iron Liposome/Water Partition Coefficients and Identification of Influencing Factors

Ferric citrate liposomes (FAC-Lip) and heme liposomes (Heme-Lip) were successfully prepared by a rotary-evaporated film-ultrasonication method. The release of iron liposomes were studied in vitro, and results showed that both iron liposomes had sustained-released properties, with Heme-Lip showing superior sustained-released over FAC-Lip. The liposome/water partition coefficients (P) were determined by equilibrium dialysis and the influences on P were evaluated, as well as the binding Gibbs free energy between FAC (Heme) and liposome. The results show that P initially increased and then decreased with increasing cholesterol content and the ratio of lipid to drug. The hydrogen and electrostatic interactions were largest when P was at its maximum. At the dialysis equilibrium, the binding Gibbs free energies (Delta G) of FAC-Lip and Heme-Lip were -12.7 and -18.2 kJ . mol(-1), respectively.