新的肾功能显像剂^(99m)Tc—EC的研究

The study of a new renal functional agent of ^(99m)Tc-EC

报道了采用直接标记及配体(^(99m)Tc-葡庚糖酸钠)交换法制备^(99m)Tc-EC的两种方法;TLC和HPLC检测标记率及放化纯均大于95％,对影响标记的各种因素作了研究。实验表明,pH对标记的影响很大,直接标记时,EC溶液的pH必须大于10,而配体交换标记时,pH只须大于8;小鼠体内分布,1min肾为14.55％I.D/organ,肾/肝3.39,10min肾为3.11％I.D/organ,肾/肝1.59。小鼠血药动力学研究表明^(99m)Tc-EC的血液清除率快,T_(1/2)α为3.9min,T_(1/2)β为39.6min,CL=1.32ml/min。兔γ显像显示,^(99m)Tc-EC在肾中浓聚高,并经肾脏快速排泄,提示^(99m)Tc-EC是一种很有前途的肾功能显像剂。

99mTc-EC (L,L ethylenedicystein) is a new renal functional agent. The preparation and its radiochemistry study, animal study were reported in the paper. 99mTc-EC can he easily prepared by two methods, one is direct labelling without boiling, the other is ligand exchange labelling. Labelling yield and radiochemical purity of 99mTc-EC were both better than 95% as confirmed by TLC and HPLC. Study on the influence of labelling conditions on radiochemical purity showed that pH is the most important influence factor: it must be over 10 in direct labelling, but may be as low as 8 for ligand exchange labelling. Renograms in rabbits showed that the T1/2 and Tmax of 99mTc EC are similar to that of131I-OIH. In mice, the biodistribution in kidneys was 14.55 and 3.11 (% I.D/organ) at 1 and 10min postinjection. The simple labelling procedure for 99mTc-EC and its good biological characteristics make it a more practical tracer agent than 99mI-OIH and 99mTc-MAG3 for renal functional study.