Rapid, one-step, high yielding<sup>18</sup>F-labeling of an aryltrifluoroborate bioconjugate by isotope exchange at very high specific activity
作者:Zhibo Liu、Ying Li、Jerome Lozada、Jinhe Pan、Kuo-Shyan Lin、Paul Schaffer、David M. Perrin
DOI:10.1002/jlcr.2990
日期:2012.12
A rapid, single step, aqueous 18F-labeling method that proceeds under mild conditions to provide radiotracers in high radiochemical yield and at high specific activity represents a long-standing challenge. Arylboronates capture aqueous 18F-fluoride ion in buffered pH 2–3 at moderate temperature to provide a highly polar 18F-ArBF3− anion. Similarly, 19F-18F isotope exchange on a 19F-ArBF3− should create an 18F-ArBF3−. We hypothesized that this reaction would proceed in volumes that would be amenable to the high levels of 18F-activity used in clinical hospitals. In order to measure both radiochemical and chemical yields, along with specific activity, we linked an alkyne-19F-ArBF3− to rhodamine azide by standard click chemistry to afford a precursor Rh-19F-ArBF3−. This precursor was aliquoted in portions of 50 nmol and lyophilized for on-demand use. Using robotic manipulators in a hot cell, we combined >29.6 GBq (800 mCi) and 50 nmol of the Rh-19F-ArBF3− in aqueous dimethylformamide at buffered pH 2–3. Following mild heating (40 °C) for 10-15 min, the reaction was quenched and analyzed. We observed radiochemical yields of 50% and specific activities of nearly 555 GBq/µmol (15 Ci/µmol). Similar radiochemical yields and slightly lower specific activities were also obtained with ~400 mCi (n = 2). With radiochemical yields in the hundreds of millicuries and specific activities that are 3–10-fold higher than most radiotracers, this method is very attractive method for preparing clinically useful radiotracers. Moreover, the ability to produce tracers at extraordinarily high specific activities expands the distribution time window from production labs to distant positron emission tomography scanners. Copyright © 2012 John Wiley & Sons, Ltd.
快速、单步、水性 18F 标记方法在温和条件下进行,以高放射化学产率和高比活度提供放射性示踪剂,这是一个长期存在的挑战。芳基硼酸盐在中等温度下在缓冲 pH 2-3 中捕获水性 18F-氟离子,以提供高极性的 18F-ArBF3− 阴离子。类似地,19F-ArBF3− 上的 19F-18F 同位素交换应产生 18F-ArBF3−。我们假设这种反应的发生量将适合临床医院使用的高水平 18F 活性。为了测量放射化学和化学产率以及比活性,我们通过标准点击化学将 alkyne-19F-ArBF3− 与罗丹明叠氮化物连接起来,得到前体 Rh-19F-ArBF3−。将该前体以50nmol的份等分并冻干以供按需使用。在热室中使用机器人操纵器,我们将 >29.6 GBq (800 mCi) 和 50 nmol 的 Rh-19F-ArBF3− 在缓冲 pH 2-3 的二甲基甲酰胺水溶液中混合。温和加热(40°C)10-15分钟后,猝灭反应并进行分析。我们观察到放射化学产率为 50%,比活度接近 555 GBq/μmol (15 Ci/μmol)。使用约 400 mCi (n= 2) 也获得了类似的放射化学产率和略低的比活度。该方法的放射化学产率高达数百毫居里,比活度比大多数放射性示踪剂高 3-10 倍,对于制备临床有用的放射性示踪剂来说是非常有吸引力的方法。此外,以极高的比活度生产示踪剂的能力扩大了从生产实验室到远距离正电子发射断层扫描仪的分配时间窗口。版权所有 © 2012 约翰·威利父子有限公司