^131I标记肿瘤血管靶向多肽的实验研究

设计合成含精氨酸-精氨酸-亮氨酸（RRL）序列的多肽，并用氯胺-T法对其进行^131I标记，标记率约60％，放化纯度〉99％。体外放置24h放化纯度仍≥90％。肿瘤对^131I标记多肽的摄取在注射后明显高于其他器官，注药后24h，肿瘤对^131I-多肽的摄取约为0．65％ID／g，肿瘤与肌肉的放射性摄取比（T／NT）达9．08。以上结果表明：通过氯胺-T法对该多肽进行^131I标记是可行的，标记物可在体外稳定存放24h；^131I-多肽可以靶向肿瘤血管，有进一步研究的价值。

Experimental Study on the Labeling of Arginine-arginine-leucine Peptide With 131I

A radioiodinated peptide of arginine-arginine-leucine（RRL） for tumor angiogenic endothelium imaging was designed and synthesized. Radioiodination of the RRL peptides was performed by the chloramine-T method. ^131I labeled peptides was injected into the nude mice bearing human prostate carcinoma via tail vein. Biodistribution results in vivo was obtained. HPLC of the crude product yielded a main peak containing 99.56% of the absorbance at 220 nm. The ^131I labeling rate of RRL peptides was about 60 %. The radiochemical purity was more than 99%. The radiochemical purity of the labeled compound remained 90% at 24 h in human blood serum at 37 ~C. In the biodistribution studies, the ^131I labeled RRL peptide accumulated in the tumor to a higher level than in the other organs, the uptake was about 0. 65% ID/g, and the radiouptake ratio of tumor to non-tumor （T/NT） was 9.08.