量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum and Radiological Science and Technology.
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Objectives: Translocator protein (18 kDa) (TSPO), a nucleus-encoded mitochondrial target transmembrane protein,
has been indicated as an active participant in the modulation of mitochondrial function. PET using radiolabeled TSPO
probes has allowed non-invasive and reliable investigation of TSPO in neuropathological damages of experimental
animals and humans. Many PET probes for TSPO imaging have been developed. Among them, [18F]FEDAC has
potent binding affinity and selectivity for TSPO [1], high signal to neuroinflammation [2], and high sensitivity and
specificity for detection of fatty liver diseases progression [3]. We had previously synthesized [18F]FEDAC by reaction
of desmethyl-precursor with [18F]fluoroethyl bromide at two steps using a modified 18F-labelling synthesizer
developed in our institute [1-3]. In this study, we simplified the synthesis of [18F]FEDAC by direct 18F-fluorination
using a typical 18F-labelling synthesizer to transfer the preparation of [18F]FEDAC to other institutes toward
multicenter clinical study.
Methods: Tosylate-precursor for radiosynthesis of [18F]FEDAC was synthesized according to the procedures, as
shown in Fig. 1. [18F]FEDAC was prepared by heating the tosylate-precursor with 18F- in DMSO at 110 ⁰C for 10-15
min.
Results: Tosylate-precursor of [18F]FEDAC was successfully synthesized from desmethyl-precursor. [18F]FEDAC
was obtained with sufficient radioactivity and suitable quality for injection in clinical application. The synthesis of [18
F]FEDAC was reproduceble to achieve >740 MBq, >300 GBq/μmol and >97% of radiochemical purity within 70 min of
an overall synthesis time. All other analytical results were in compliance with our in-house quality control and
assurance specifications.
Conclusions: We successfully synthesized [18F]FEDAC by fluorination of the tosylate-precursor with 18F- using onepot
18F-labelling synthesizer. This radioligand will be used in clinical study.
References: [1] Yanamoto K, et al (2009), Bioorg Med Chem Lett, 19, 1707-10. [2] Yui J, et al (2010), J Nucl Med, 51,
1301-9. [3] Xie L, et al (2012), J Hepatol, 57, 1076-82.
会議概要（会議名, 開催地, 会期, 主催者等）
21st International Symposium on Radiopharmaceutical Sciences
One-pot radiosynthesis of [18F]FEDAC as a clinically applicable PET ligand for imaging TSPO.
