作者:Vanessa Gómez-Vallejo、Mikel González-Esparza、Jordi Llop
DOI:10.1002/jlcr.2979
日期:2012.11
[11C]Me-QNB is a muscarinic acetylcholinergic receptor antagonist that has been used for the assessment of myocardial muscarinic receptors density in different cardiovascular pathologies. In the current technical note, we report a facile, highly efficient and fully automated method for the preparation of this radiotracer. The radiosynthesis was performed by reaction of [11C]CH3I with the desmethylated precursor (QNB) at room temperature using the captive solvent method. Excellent radiochemical yield (91.1 ± 2.4%, decay-corrected) and radiochemical purity (>99.5%), and good specific activity (137 ± 5 GBq/µmol) were obtained when the purification was performed by reverse phase HPLC in overall synthesis time <31 min. Purification using solid-phase extraction offered lower radiochemical yield (27.6 ± 3.1%, decay-corrected) and radiochemical purity (>95%) but higher specific activity (244 ± 18 GBq/µmol) in shorter reaction times (<21 min). These results, especially concerning radiochemical yield, significantly improve those previously reported in which the reaction was performed in a vial and the purification step was based on ionic chromatography.
[11C]Me-QNB 是一种对乙酰胆碱能受体的穆斯卡林拮抗剂,用于评估不同心血管疾病中的心肌穆斯卡林受体密度。在当前的技术笔记中,我们报告了一种简便、高效且完全自动化的放射性示踪剂制备方法。通过将 [11C]CH3I 与去甲基前体(QNB)在室温下采用捕获溶剂法反应进行放射性合成。当通过反相高效液相色谱进行纯化时,获得了优异的放射化学产率(91.1 ± 2.4%,衰变校正)和放射化学纯度(>99.5%),以及良好的比活性(137 ± 5 GBq/µmol),整体合成时间小于31分钟。使用固相萃取的纯化提供了较低的放射化学产率(27.6 ± 3.1%,衰变校正)和放射化学纯度(>95%),但在更短的反应时间内(<21分钟)获得了更高的比活性(244 ± 18 GBq/µmol)。这些结果,特别是关于放射化学产率的部分,显著改善了以前报告的结果,在那些研究中反应是在小瓶中进行,纯化步骤基于离子色谱法。