• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.1
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• pp.27-38
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• 2020

Alzheimer's disease (AD) is one of the challenging conditions that have no cure, yet early diagnosis can help to control the disease. PET imaging of tau has several advantages, such as being a noninvasive, safe diagnostic technique that correlates directly with the disease progression. Many tau tracers have been reported to date; however, the chemical scaffolds of them fall in a narrow chemical window, and none was approved yet as none is entirely selective and sensitive to tau. These problems are being solved as new tracers emerge constantly. In this report, the first-generation tau tracers such as [¹¹C]PBB3, 2-arylquinoline (THK) series, [¹⁸F]T808, and [¹⁸F]AV-1451 ([¹⁸F]T807) are reviewed from an organic and radiochemistry perspective; thus the most effective chemical approach to synthesize these tracers is discussed. This would help to design novel tracers which can meet the challenges faced by the current tracers.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.2
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• pp.61-68
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• 2020

Aggregated neurofibrillary tangles (NFTs) are a pathological hallmark in Alzheimer's disease (AD) and many radiopharmaceuticals targeting NFTs have been developed so far. Among these, [¹⁸F]flortaucipir (TAUVID^TM) is the first approved radiopharmaceutical in the Food and Drug Administration (FDA) to image tau pathology. In the present study, we describe the optimized radiosynthetic method for the routine production of [¹⁸F] flortaucipir using a commercialized automation module (i.e. GE TRACERlab^TM FX_FN pro). [¹⁸F]Flortaucipir was prepared by nucleophilic substitution from its N-tert-butoxycarbonyl protected nitro precursor, tertbutyl 7-(6-nitropyridin-3-yl)-5H-pyrido[4,3-b]indole-5-carboxylate, at 130℃ for 10 min in dimethyl sulfoxide. The mean radiochemical yield was 20 ± 4.3% (decay-corrected, n = 47) with the molar activity of 218 ± 32 GBq/µmol at the end of synthesis. The radiochemical purity was determined to be above 95%. The overall production time including quality control is approximately 100min. The final produced [¹⁸F]flortaucipir injection meets the USP criteria for quality control. Thus, this fully automated system is validated for clinical use.