DECORPORATION OF TH-228 FROM THE RAT BY 3,4,3-LIHOPO AND DTPA AFTER SIMULATED WOUND CONTAMINATION

1 With DTPA as a comparison, the siderophore analogue 3,4,3-LIHOPO has been examined for its ability to remove Th-228 nitrate from the rat a fter subcutaneous (sc) and intramuscular (im) injection to simulate wo und contamination. The commencement of treatment was delayed 30 min, 6 h or 1 d and the animals killed at 7 d. 2 In all cases 3,4,3-LIHOPO w as appreciably more effective than DTPA although the efficacy of treat ment and the relative effectiveness of the ligands decreased rapidly w ith their delay in administration. 3 Optimum removal with bath ligands occurred when initial local administration at 30 min after exposure w as followed by repeated intraperitoneal injection at 6 h, 1, 2 and 3 d . Under these conditions the body content of Th-228 was reduced to 20% of controls after sc injection and 15% after im injection. The corres ponding values using repeated DTPA administration were 80% and 54%. 4 It is concluded that 3,4,3-LIHOPO represents, potentially, a considera ble advance on DTPA, the current agent of choice for the treatment of wounds contaminated by Th-228.