中文摘要：

通过体内、外实验,研究了游离^125I与血浆蛋白的结合及其在三氯乙酸（TCA）沉淀后的沉淀百分率,并与^125I-RGD-Sak在SD大鼠中不同时间血药浓度的结果进行了比较.结果表明,游离^125I能与血浆蛋白结合,并为TCA所沉淀,且在一定范围内,游离^125I与血浆蛋白结合后的沉淀百分率与温育时间及游离^125I的活度无关.体内、外实验中,游离^125I与血浆蛋白结合后的沉淀百分率分别为（1.26±0.14）%及（1.38±0.33）%.沉淀物中含有吸附在沉淀物表面的游离^125I,该吸附需要用TCA沉淀2～3次才能去除.采用^125I核素示踪法进行生物类制品的药代动力学研究时,应对游离^125I的影响进行校正.

英文摘要：

The aim of this study was to investigate the influence of ionic ^125I on the results of pharmacokinetics study for biologic products. The ionic ^125I bound to plasma protein was studied through measuring precipitation rates of plasma protein bound ionic ^125I after TCA precipitation in vitro and in vivo, with which precipitation rates of ^125I-RGD-Sak in plasma of SD rats at different time were compared. The results of the experiment show that ionic ^125I could be bound to plasma protein and be deposited by TCA [ in vitro ： （ 1.26 ± 0. 14） % ; in vivo ： （1.38 ±0.33）% ]. The precipitation rates were independent of the reaction time（ 10 to 1440 min） and ionic ^125I activity（ 14500 to 120000 count/min）. Also, ionic ^125I attached to the surface of precipitate contributed a lot to the precipitation rate, which could be eliminated after 2 to 3 times TCA precipitation. The influence of the ionic ^125I should be calibrated in ^125I tracing method applied to pharmacokinetics study for biological products.