摘要
The cyclic peptide YG5 and the t-butyloxycarbonyl(Boc)-modified analog(Boc-YG5) were labeled with radioiodine.The radiochemical purity of 131I-YG5 or 131I-Boc-YG5 was almost 100% after purification by RP-HPLC.Biodistribution in BALB/C nude mice bearing MCF-7 tumor was measured.After t-butyloxycarbonyl(Boc)-modification,the 131I-Boc-YG5 was quite resistant to deiodination in vivo,resulting in negligible radioactivity accumulation in thyroid.The radiotracer clearance in tumor became faster,the absolute tumor uptake decreased for 131I-Boc-YG5,but the tumor-to-tissue uptake ratios increased.The uptake ratios of tumor to muscle,blood,heart,and lung at 1 h post injection reached 4.73,1.70,4.09 and 1.70,respectively.It is demonstrated that Boc-group is an effective prosthetic one to prevent deiodination in vivo and improve tumor imaging for radioiodinated NGR.
The cyclic peptide YG5 and the t-butyloxycarbonyl（Boc）-modified analog（Boc-YG5） were labeled with radioiodine.The radiochemical purity of ^131I-YG5 or ^131I-Boc-YG5 was almost 100% after purification by RP-HPLC.Biodistribution in BALB/C nude mice bearing MCF-7 tumor was measured.After t-butyloxycarbonyl（Boc）-modification,the ^131I-Boc-YG5 was quite resistant to deiodination in vivo,resulting in negligible radioactivity accumulation in thyroid.The radiotracer clearance in tumor became faster,the absolute tumor uptake decreased for ^131I-Boc-YG5,but the tumor-to-tissue uptake ratios increased.The uptake ratios of tumor to muscle,blood,heart,and lung at 1 h post injection reached 4.73,1.70,4.09 and 1.70,respectively.It is demonstrated that Boc-group is an effective prosthetic one to prevent deiodination in vivo and improve tumor imaging for radioiodinated NGR.
基金
Support by National Natural Science Foundation of China (No. 20771011 and 21071010)
the Ministry of Science and Technology of China (No. 2006CB705700)
