EARLY CHELATION-THERAPY FOR INJECTED PU-238 AND AM-241 IN THE RAT - COMPARISON OF 3,4,3-LIHOPO, DFO-HOPO, DTPA-DX, DTPA AND DFOA

Chelating agents were tested for removal of simultaneously injected Pu-238 and Am-241 from the rat. The effectiveness of early single chelate injections on Pu-238 retention in tissues decreased in the order 3,4,3-LIHOPO > DFO-HOPO > DTPA > DTPA-DX, and for Am-241 in the order 3,4,3-LIHOPO > DTPA-DX > DTPA much greater than DFO-HOPO. DTPA-DX showed a special ability to remove Am-241 from the liver. Injected 3,4,3-LIHOPO decreased the contents of Pu-238 in bone and liver to 9 and 3%, respectively, of those in untreated controls. Corresponding values for Am-241 in bone and liver were 30 and 6%, respectively, which indicates that 3,4,3-LIHOPO (unlike DFO-HOPO) is not a plutonium-specific chelator. The effectiveness of prompt single oral treatment with 3,4,3-LIHOPO and DFO-HOPO in reducing retention of actinides was comparable with that of these chelators injected with 1 h delay and at one-third of the oral dose. When 3,4,3-LIHOPO was administered by continuous infusion, a superior effect was achieved with total chelate amounts only slightly exceeding that given as single injection. The retention of PU-238 and Am-241 in bones was reduced to < 5 and 10% of controls, respectively; the contents in the liver were < 2% of controls.