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Automated one‐step radiosynthesis of the CB 1 receptor imaging agent [ 18 F]MK‐9470
Author(s) -
Thomae David,
Morley Thomas J.,
Hamill Terence,
Carroll Vincent M.,
Papin Caroline,
Twardy Nicole M.,
Lee H. Sharon,
Hargreaves Richard,
Baldwin Ronald M.,
Tamagnan Gilles,
Alagille David
Publication year - 2014
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.3219
Subject(s) - radiosynthesis , chemistry , yield (engineering) , radiochemistry , radioligand , specific activity , pet imaging , chemical synthesis , alkylation , stereochemistry , positron emission tomography , nuclear medicine , receptor , organic chemistry , medicine , biochemistry , materials science , metallurgy , in vitro , enzyme , catalysis
The fluorine‐18‐labeled positron emission tomography (PET) radiotracer [ 18 F]MK‐9470 is a selective, high affinity inverse agonist that has been used to image the cannabinoid receptor type 1 in human brain in healthy and disease states. This report describes a simplified, one‐step [ 18 F]radiofluorination approach using a GE TRACERlab FX FN module for the routine production of this tracer. The one‐step synthesis, by [ 18 F]fluoride displacement of a primary tosylate precursor, gives a six‐fold increase in yield over the previous two‐step method employing O ‐alkylation of a phenol precursor with 1,2‐[ 18 F]fluorobromoethane. The average radiochemical yield of [ 18 F]MK‐9470 using the one‐step method was 30.3 ± 11.7% ( n = 12), with specific activity in excess of 6 Ci/µmol and radiochemical purity of 97.2 ± 1.5% ( n = 12), in less than 60 min. This simplified, high yielding, automated process was validated for routine GMP production of [ 18 F]MK‐9470 for clinical studies.