Galactosylated liposomes as carriers for targeting meso-2,3-dimercaptosuccinic acid to cadmium storage sites in cadmium exposed mice.

In this study an attempt has been made to examine the efficacy of meso-2,3-dimercaptosuccinic acid (DMSA) using galactosylated liposomes as carriers for mobilization of cadmium from the body of mice preexposed to cadmium chloride (0.005 mmoles/kg intraperitoneally daily for 4 days). Cadmium-exposed mice after a rest period of 8 weeks were administered DMSA intravenously, two injections 15 micromoles/kg with an interval of 48 h, as free form of DMSA, or DMSA encapsulated in liposomes composed of phosphatidyl choline, cholesterol and phosphatidyl ethanolamine (7:2:1; PC-lip-DMSA) or in liposomes to which p-aminophenyl galactoside had been anchored (Gal-lip-DMSA). Excretion of cadmium through urine and feces was monitored for 5 days. Thereafter animals were sacrificed, liver, kidneys, spleen and isolated hepatocytes were analysed for cadmium, copper and zinc concentration. Efficacy for cadmium mobilization from the body was found to be in the order Gal-lip-DMSA>PC-lip-DMSA>DMSA. These results show that liposomes can be used as targeted carrier system for chelating agents safely and efficiently as compared to administration of free chelating agent.