Efficacy of 3,4,3-LIHOPO for reducing neptunium retention in the rat aftersimulated wound contamination

Purpose: The ligand 3,4,3-Li(1,2-HOPO) was tested for Np removal after intr amuscular injection of Np-237 nitrate in rats. Materials and methods: Two experiments were performed, one with simultaneou s injection of neptunium and LIHOPO at dosages ranging from 3 to 200 mu mol kg(-1) and the other with delayed administration of LIHOPO 30 mu mol kg(-1 ) from 5 min to 30 min after Np injection. Results: The data obtained after simultaneous injections showed that the li gand dosage effectiveness was not linear and depended on the tissues being considered. For bones, the best results were obtained with 200 mu mol kg(-1 ) LIHOPO, where retention was reduced to 11% of controls. Maximum efficacie s for removal in liver and kidney were obtained with 30 mu mol kg(-1) LIHOP O, where retention was reduced to 39% and 1.6% of controls, respectively. A r higher dosages, LIHOPO seemed to have a reverse effect on these tissues, demonstrated by a significant accumulation of the radionuclide. The delayed administration of LIHOPO dramatically decreased its efficacy. When adminis tered 5 min after Np, LIHOPO was still efficient (60%, 37%, 7% of controls in bone, liver, kidneys, respectively) but not when treatment was delayed t o 30 min. Conclusions: These results demonstrated that LIHOPO was able to complex Np at the wound site but nor after translocation to blood.