Decorporation of thorium-228 from the rat by 3,4,3-LIHOPO and DTPA after simulated wound contamination

Abstract

1 With DTPA as a comparison, the siderophore analogue 3,4,3-LIHOPO has been examined for its ability to remove ²²⁸Th nitrate from the rat after subcutaneous (sc) and intramuscular (im) injection to simulate wound contamination. The commencement of treat ment was delayed 30 min, 6 h or 1 d and the animals killed at 7 d.

2 In all cases 3,4,3-LIHOPO was appreciably more effec tive than DTPA although the efficacy of treatment and the relative effectiveness of the ligands decreased rapidly with their delay in administration.

3 Optimum removal with both ligands occurred when initial local administration at 30 min after exposure was followed by repeated intraperitoneal injection at 6 h, 1, 2 and 3 d. Under these conditions the body con tent of ²²⁸Th was reduced to 20% of controls after sc injection and 15% after im injection. The correspond ing values using repeated DTPA administration were 80% and 54%.

4 It is concluded that 3,4,3-LIHOPO represents, poten tially, a considerable advance on DTPA, the current agent of choice for the treatment of wounds contami nated by ²²⁸Th.