多发性硬化症显像剂11C-CIC的合成

Synthesis of 11C-CIC for PET Imaging of Multiple Sclerosis

  • 摘要: 自动化合成了靶向髓磷脂(myelin)的PET显像剂4-(4-(4-氨基苯乙烯基)-2,5-二甲氧基苯乙烯基)-N-甲基-11碳苯胺(11C-CIC),通过研究其在小鼠生物体及大鼠大脑中的分布,判断其作为多发性硬化(multiple sclerosis, MS)诊断或疗效评价的可行性。在多功能模块上将11C-CH3-Triflate直接与前体反应,经HPLC分离、纯化得到11C-CIC,采用NH小鼠用于研究11C-CIC的生物学分布,Wistar大鼠行Micro PET/CT显像。11C-CIC合成效率为55%~65%(n>10),放化纯度大于99%,比活度为60 GBq/μmol。11C-CIC的体外稳定性较差,加入10 g/L的抗坏血酸能防止其分解。11C-CIC初始脑摄取为2.78%ID/g,放射性主要通过肝、肾排泄。Micro PET/CT显像表明,大鼠大脑对11C-CIC摄取较好。结果表明,制备11C-CIC时需加入抗坏血酸以提高其体外稳定性,11C-CIC有可能应用于髓鞘斑显像,用于诊断或评价MS的进展。

     

    Abstract: Multiple sclerosis (MS) is an inflammatory neurodegenerative disorder of central nervous system. Imaging of myelin tracts in vivo would greatly improve the diagnosis and monitoring of MS. The 11C-CIC was synthesized with 11C-CH3-Triflate at high yields, and was confirmed by biodistribution and imaging. 11C-CH3-Triflate was distilled and trapped into a reaction vial containing the 2 mg precursor. The final production was purified by semi-HPLC to get 11C-CIC. The in vitro stability of 11C-CIC was studied at RT with or without Vc. The normal NH mice were sacrificed at different time after injection of 11C-CIC for biodistribution. The micro PET/CT was performed at 30 min post-injection. The radiochemical yield was 55%65% decay corrected to 11CH3-Triflate. The radiochemical purity was over 99% at specific activity of 60 GBq/μmoL. The HPLC showed the poor stability of 11C-CIC in vitro. The 11C-CIC was very stable after the 10 g/L Vc used as stabilizer. The initial uptake of the cerebrum was 2.78%ID/g. The radioactivity were excreted from the digestive system and urine. The micro PET/CT imaging showed good uptake in the cerebrum. The stability of 11C-CIC can be improved with Vc as stabilizer. The11C-CIC was a candidate for imaging of myelin tracts for diagnosis or monitor MS.

     

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