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A report of the automated radiosynthesis of the tau positron emission tomography radiopharmaceutical, [ 18 F]‐THK‐5351
Author(s) -
Neelamegam Ramesh,
Yokell Daniel L.,
Rice Peter A.,
Furumoto Shozo,
Kudo Yukitsuka,
Okamura Nobuyuki,
El Fakhri Georges
Publication year - 2017
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.3482
Subject(s) - radiosynthesis , chemistry , radiochemistry , potassium fluoride , fluoride , nuclear chemistry , yield (engineering) , specific activity , nucleophile , positron emission tomography , inorganic chemistry , nuclear medicine , catalysis , organic chemistry , medicine , materials science , metallurgy , enzyme
The radiotracer, [ 18 F]‐THK‐5351, is a highly selective and high‐binding affinity PET imaging agent for aggregates of hyper‐phosphorylated tau protein. Our report is a simplified 1‐pot, 2‐step radiosynthesis of [ 18 F]‐THK‐5351. This report is broadly applicable for routine clinical production and multi‐center trials on account of favorable half‐life of flourine‐18 and the use of a commercially available radiosynthesis module, the GE TRACERlab™ FX FN . First, the O‐THP protected tosyl precursor underwent nucleophilic fluorinating reaction with potassium cryptand fluoride ([ 18 F] fluoride (K[ 18 F]/K 222 )) in Dimethyl sulfoxide at 110°C for 10 minutes followed by O‐THP removal by using diluted hydrochloric acid (HCl) at same temperature. [ 18 F]‐THK‐5351 was purified via semi‐preparative high‐performance liquid chromatography and formulated by using 10% EtOH, United States Pharmacopeia (USP) in 0.9% sodium chloride for injection, USP and an uncorrected radiochemical yield of 21 ± 3.5%, with a specific activity of 153.11 ± 25.9 GBq/μmol (4138 ± 700 mCi/μmol) at the end of synthesis (63 minutes; n = 3).