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Facile and improved synthesis of [ 11 C]Me‐QNB
Author(s) -
GómezVallejo Vanessa,
GonzálezEsparza Mikel,
Llop Jordi
Publication year - 2012
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.2979
Subject(s) - chemistry , radiosynthesis , yield (engineering) , specific activity , chromatography , solvent , muscarinic antagonist , extraction (chemistry) , muscarinic acetylcholine receptor , radiochemistry , high performance liquid chromatography , solid phase extraction , solvent extraction , nuclear chemistry , receptor , organic chemistry , in vivo , biochemistry , materials science , microbiology and biotechnology , metallurgy , biology , enzyme
[ 11 C]Me‐QNB is a muscarinic acetylcholinergic receptor antagonist that has been used for the assessment of myocardial muscarinic receptors density in different cardiovascular pathologies. In the current technical note, we report a facile, highly efficient and fully automated method for the preparation of this radiotracer. The radiosynthesis was performed by reaction of [ 11 C]CH 3 I with the desmethylated precursor (QNB) at room temperature using the captive solvent method. Excellent radiochemical yield (91.1 ± 2.4%, decay‐corrected) and radiochemical purity (>99.5%), and good specific activity (137 ± 5 GBq/µmol) were obtained when the purification was performed by reverse phase HPLC in overall synthesis time <31 min. Purification using solid‐phase extraction offered lower radiochemical yield (27.6 ± 3.1%, decay‐corrected) and radiochemical purity (>95%) but higher specific activity (244 ± 18 GBq/µmol) in shorter reaction times (<21 min). These results, especially concerning radiochemical yield, significantly improve those previously reported in which the reaction was performed in a vial and the purification step was based on ionic chromatography.