Intracellular plutonium: removal by liposome-encapsulated chelating agent

Chelating agents, such as ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) were successfully encapsulated within lipid spherules (that is, liposomes). Encapsulated [ 14 C]EDTA, given intravenously to mice, was retained longer in tissues than nonencapsulated [ 14 C]EDTA. Encapsulated DTPA, given to mice 3 days after plutonium injection, removed an additional fraction of plutonium in the liver, presumably intracellular, not available to nonencapsulated DTPA. It also further increased urinary excretion of plutonium. Introduction of chelating agents into cells by liposomal encapsulation is a promising new approach to the treatment of metal poisoning.