AUTHOR=Dai Yuyin , Sa Ri , Guan Feng , Wang Qi , Li Yinghua , Zhao Hongguang 

TITLE=A Purification Method of 18F-FP-(+)-DTBZ via Solid-Phase Extraction With Combined Cartridges

JOURNAL=Frontiers in Medicine

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2021.693632

DOI=10.3389/fmed.2021.693632

ISSN=2296-858X

ABSTRACT=<p><bold>Background:</bold> To optimize [<sup>18</sup>F] 9-fluoropropyl-(+)-dihydrotetrabenazine (<sup>18</sup>F-FP-(+)-DTBZ) purification via solid-phase extraction (SPE) with combined cartridges to facilitate its widespread clinical application.</p><p><bold>Methods:</bold> A modified SPE purification method, employing Sep-Pak PS-2 and Sep-Pak C18 cartridges, was used for the preparation of <sup>18</sup>F-FP-(+)-DTBZ. This method was compared to the purification method of high-pressure liquid chromatography (HPLC) and SPE with one cartridge, following quality control test and positron emission tomography (PET) imaging in healthy volunteers and patients with parkinsn's disease (PD).</p><p><bold>Results:</bold> A SPE purification method integrating Sep-Pak PS-2 and Sep-Pak C18 cartridges was implemented successfully. The retention time of <sup>18</sup>F-FP-(+)-DTBZ purified by HPLC, SPE with Sep-Pak PS-2, SPE with Sep-Pak C18, and SPE with combined use of Sep-Pak PS-2 and Sep-Pak C18 cartridges was 8.7, 8.8, 8.7, and 8.9 min, respectively. Fewest impurity peak was detected in <sup>18</sup>F-FP-(+)-DTBZ purified by the SPE with combined use of Sep-Pak PS-2 and Sep-Pak C18 cartridges. This modified SPE purification method provided a satisfactory radiochemical yield of 29 ± 1.8% with radiochemical purity &gt;99% and shortened synthesis time to 27 min. The brain uptake of <sup>18</sup>F-FP-(+)-DTBZ purified by the modified SPE was comparable to that purified by HPLC in both healthy volunteers and PD patients.</p><p><bold>Conclusions:</bold> A SPE method integrating Sep-Pak PS-2 and Sep-Pak C18 cartridges for purification of <sup>18</sup>F-FP-(+)-DTBZ may be highly suited to automatic synthesis for routine clinical applications, as it provides excellent radiochemical purity, high yield as well as operational simplicity.</p>