Comparative efficacies of 3,4,3-LIHOPO and DTPA for enhancing the excretion of plutonium and americium from the rat after simulated wound contamination as nitrates

With DTPA as a comparison, the siderophore analogue 3,4,3-LIHOPO has been examined for its ability to remove ²³⁸Pu and ²⁴¹Am from the rat after subcutaneous (s.c.) and intramuscular (i.m.) injection of about 200 Bq of each actinide (0.3 ng Pu, 1.6 ng Am). After the s.c. deposition of ²³⁸Pu and ²⁴¹Am, both ligands were more effective after local administration than (in decreasing order) their repeated interperitoneal (i.p.) injection, single i.p. injection and continuous infusion. Dosages of 3 μmol kg^-1 of 3,4,3,-LIHOPO were at least as effective as 30 μmol kg^-1 DTPA after each mode of administration. The most effective regimen of those investigated for s.c. ²³⁸Pu and ²⁴¹Am involved local administration of 30 μmol kg^-1 of 3,4,3-LIHOPO at 30 min followed by i.p. injections at 6 h, 1, 2 and 3 day. By day 7 after exposure, the amounts of ²³⁸Pu and ²⁴¹Am retained in the body were 2 and 7% of those in controls, respectively and 10 and four times less than when DTPA was administered using the same regimen. The ligand 3,4,3-LIHOPO was more effective for ²³⁸Pu and ²⁴¹Am after their i.m. injection. This was attributed to the greater retention of these actinides at the wound site (97 versus 67%) when treatment commenced. After a single local injection of 30 μmol kg^-1 at 30 min, the amounts of ²³⁸Pu and ²⁴¹Am retained in the body at 7 day were 0.9 and 0.8% of controls. These values were 34 and 27 times less than after local and repeated i.p. injections of DTPA at dosages of 30 μmol kg^-1.