Microfluidic radiosynthesis and biodistribution of [<sup>18</sup>F] 2-(5-fluoro-pentyl)-2-methyl malonic acid
作者:Gajanan K. Dewkar、Gobalakrishnan Sundaresan、Narottam Lamichhane、Jerry Hirsch、Celina Thadigiri、Thomas Collier、Matthew C. T. Hartman、Ganesan Vaidyanthan、Jamal Zweit
DOI:10.1002/jlcr.3016
日期:2013.5.15
Microfluidics technology has emerged as a powerful tool for the radiosynthesis of positron emission tomography (PET) and single-photon emission computed tomography radiolabeled compounds. In this work, we have exploited a continuous flow microfluidic system (Advion, Inc., USA) for the [18F]-fluorine radiolabeling of the malonic acid derivative, [18F] 2-(5-fluoro-pentyl)-2-methyl malonic acid ([18F]-FPMA), also known as [18F]-ML-10, a radiotracer proposed as a potential apoptosis PET imaging agent. The radiosynthesis was developed using a new tosylated precursor. Radiofluorination was initially optimized by manual synthesis and served as a basis to optimize reaction parameters for the microfluidic radiosynthesis. Under optimized conditions, radio-thin-layer chromatography analysis showed 79% [18F]-fluorine incorporation prior to hydrolysis and purification. Following hydrolysis, the [18F]-FPMA was purified by C18 Sep-Pak, and the final product was analyzed by radio-HPLC (high-performance liquid chromatography). This resulted in a decay-corrected 60% radiochemical yield and ≥98% radiochemical purity. Biodistribution data demonstrated rapid blood clearance with less than 2% of intact [18F]-FPMA radioactivity remaining in the circulation 60 min post-injection. Most organs showed low accumulation of the radiotracer, and radioactivity was predominately cleared through kidneys (95% in 1 h). Radio-HPLC analysis of plasma and urine samples showed a stable radiotracer at least up to 60 min post-injection.
微流体技术已成为正电子发射断层扫描(PET)和单光子发射计算机断层扫描放射性标记化合物放射合成的强大工具。在这项工作中,我们利用连续流动微流体系统(Advion, Inc., USA)对马来酸衍生物[18F] 2-(5-氟戊基)-2-甲基马来酸([18F]-FPMA),即[18F]-ML-10的[18F]氟标记进行了探索,这是一种被提议作为潜在凋亡PET成像剂的放射性示踪剂。放射合成采用了一种新的磷酸酯前体进行开发。通过手动合成初步优化了氟化反应,并作为优化微流体放射合成反应参数的基础。在优化条件下,放射薄层色谱分析显示在水解和纯化之前的[18F]-氟掺入率为79%。水解后,通过C18 Sep-Pak对[18F]-FPMA进行了纯化,最终产品通过放射性高效液相色谱(radio-HPLC)进行了分析,得到了校正后的60%放射化学产率和≥98%的放射化学纯度。生物分布数据显示,注射后60分钟内血液中剩余完整[18F]-FPMA放射性不足2%,表明快速清除。大多数器官对放射性示踪剂的积累较低,放射性主要通过肾脏排除(1小时内清除率为95%)。对血浆和尿液样品的放射性HPLC分析显示,放射性示踪剂在注射后至少稳定存在60分钟。