64Cu-NOTA-NOC的制备及体内生物分布初步研究

Preparation and Preliminary Biodistribution Study of 64Cu-NOTA-NOC

  • 摘要: 对生长抑素八肽类似物NOTA-NOC进行64Cu标记,并对64Cu-NOTA-NOC的体外稳定性、脂水分配系数、正常及荷瘤小鼠体内分布进行初步研究。建立64Cu-NOTA-NOC的标记及质控条件;考察64Cu-NOTA-NOC的体外稳定性,测定其脂水分配系数;通过尾静脉注射64Cu-NOTA-NOC至小鼠体内,进行生物分布研究。结果表明:室温条件下即可获得标记率大于95%的64Cu-NOTA-NOC;64Cu-NOTA-NOC在缓冲溶液及10%胎牛血清溶液中具有良好的稳定性,脂水分配系数为-1.12±0.005 6;64Cu-NOTA-NOC在正常昆明(KM)小鼠体内主要经肾脏代谢,血液摄取值随时间下降明显,显示其体内清除速度较快;在荷BON-1胰腺癌裸鼠体内也主要经肾脏代谢;在肿瘤中具有较高的摄取,注后2 h,肿瘤/肌肉摄取比值达10.38;荷BON-1胰腺癌裸鼠的PET/CT显像结果显示,1 h时,肿瘤对64Cu-NOTA-NOC的摄取率最高,为7.7%ID/g,而给予阻断剂后,肿瘤对64Cu-NOTA-NOC的摄取率显著降低,为0.94%ID/g。NOTA-NOC的64Cu标记在室温条件下即可完成,64Cu-NOTA-NOC在缓冲溶液及10%胎牛血清中具有较好的稳定性;其在动物体内主要经肾脏代谢,体内清除较快,在胰腺癌肿瘤组织中有较高摄取;PET/CT实验结果显示肿瘤对64Cu-NOTA-NOC的摄取具有特异性。初步的研究结果表明,64Cu-NOTA-NOC具有用于胰腺癌诊疗的潜质,值得开展进一步研究。

     

    Abstract: The radiolabeling of somatostatin octapeptide analogue NOTA-NOC with 64Cu was carried out. The preliminary study of 64Cu-NOTA-NOC on the in vitro stability, the lipid-water partition coefficient, and the distribution in normal and tumor-bearing mice was conducted. The labeling and quality control methods of 64Cu-NOTA-NOC were developed. The in vitro stability of 64Cu-NOTA-NOC was investigated in buffer solution and 10% fetal bovine serum solution at 37 ℃. The lipid-water partition coefficient of 64Cu-NOTA-NOC was also determined. Biodistribution studies were performed in normal KM mice and nude mice bearing BON-1 tumor and small-animal PET imaging studies were performed on nude mice bearing BON-1 tumor. The results showed that radiolabeling of NOTA-NOC with 64Cu was straightforward and fast (~15 min) at room temperature in high yield and >95% of radiochemical purity. 64Cu-NOTA-NOC showed good stability in buffer solution and 10% fetal bovine serum solution at 37 ℃. The value of LogP was -1.12±0.005 6 which indicated 64Cu-NOTA-NOC was hydrophilic. Biodistribution studies in normal mice revealed high uptake of radioactivity in kidneys, suggesting that 64Cu-NOTA-NOC was mainly metabolized by the kidneys, and the blood uptake decreases significantly 4 h, indicating rapid blood clearance rate. 64Cu-NOTA-NOC was mainly metabolized by the kidney in nude mice bearing BON-1 tumor. At 1 h, 2 h, 4 h, tumor uptake was (3.74±1.23)%ID/g, (4.80±0.92)%ID/g and (1.31±0.27)%ID/g respectively, and tumor/muscle ratio reached to 10.38 at 2 h. The results of PET/CT imaging of nude mice bearing BON-1 tumor showed that the tumor uptake of 64Cu-NOTA-NOC peaked at 1 h, which was 7.7%ID/g,and after co-administration of the blocker, the tumor uptake of 64Cu-NOTA-NOC was significantly reduced to 0.94%ID/g. 64Cu-NOTA-NOC could be prepared under mild reaction conditions; and it had good stability in buffer solution and 10% fetal bovine serum. 64Cu-NOTA-NOC was mainly metabolized by kidneys, and cleared fast from the body in normal mice as well as in model mice. The tumor/muscle ratio could reach 10.38 at 2 h. The results of PET/CT imaging showed that the tumor uptake of 64Cu-NOTA-NOC was specific. These results demonstrated the potential of 64Cu-NOTA-NOC in the diagnosis of SSTR positive tumors, and it is worthy of further evaluation.

     

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