LABELING OF PINGYANGMYCIN WITH ~(153)Sm AND ~(186)Re THROUGH THE CONJUGATION OF BADTPA

Pingyangmycin (PLM) is a homemade antibiotics mixture with bleomycin as its main constituent. 153 Sm or 186 Re is indirectly labeled to PLM via a conjugating chelator. Diethylenetramine penta acetic acid(DTPA)is chosen as the conjugator. The bicyclic anhydride of DTPA(BADTPA)is chosen as the conjugator. The bicyclic anhydride of DTPA(BADTPA)is coupled to PLM at room temperature to form a BADTPA PLM adduct. 153 Sm BADTPA PLM is prepared by boiling of aqueous 153 SmCl 3 and BADTPA solution mixture at pH=4～6 for 3 min. 186 Re is labeled to BADTPA PLM by reduction of 186 ReO - 4 with SnCl 2+Sn at 95 ℃ for 30 min in the presence of gluconic acid(pH=3～5). The yield in both cases in higher than 95%. The labeled compounds are stable for 48 h at least at room temperature. Their high hydrophilicity is demonstrated by their low partition coefficients between noctanol and water. The biodistribution of these labeled compounds in mice upon time is determined. The results indicate that these labeled compounds are principally excreted through blood kidney route.