title: Microwave-assisted radiosynthesis of [(18) F]ASEM, a radiolabeled α7-nicotinic acetylcholine receptor antagonist.
abstract: An improvement of the original radiochemical synthesis of [(18) F]ASEM, an α7-nicotinic acetylcholinergic receptor radioligand, is reported. The new procedure utilizes microwave-assisted radiofluorination. In addition, a new preparative HPLC method was developed to eliminate a chemical impurity in the final product. Quality control procedures were also enhanced to improve detection of product with enhanced resolution of potential impurities. [(18) F]ASEM was produced in 20.1 ± 8.9% non-decay corrected (NDC) yield with an average synthesis time of 57 min and an average specific radioactivity of 856 ± 332 GBq/µmol (23 ± 9 Ci/µmol).
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Nelson B1-152, Baltimore, MD, 21287, USA.
authors.forename: Hayden T
authors.initials: HT
authors.lastname: Ravert
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Holt
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Gao
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Horti
authors.forename: Robert F
authors.initials: RF
authors.lastname: Dannals
mesh_terms: D053961:Azabicyclo Compounds / Q000032:analysis / Q000138:chemical synthesis*; D003499:Cyclic S-Oxides / Q000032:analysis / Q000138:chemical synthesis*; D007553:Isotope Labeling / Q000379:methods*; D008872:Microwaves; D011829:Radiation Dosage; D019275:Radiopharmaceuticals / Q000032:analysis / Q000138:chemical synthesis*; D064569:alpha7 Nicotinic Acetylcholine Receptor / Q000037:antagonists & inhibitors*
chemical_list: C585155:3-(1,4-diazabicyclo(3.2.2)nonan-4-yl)-6-fluorodibenzo(b,d)thiophene 5,5-dioxide; D053961:Azabicyclo Compounds; D003499:Cyclic S-Oxides; D019275:Radiopharmaceuticals; D064569:alpha7 Nicotinic Acetylcholine Receptor
keywords: PET chemistry; [18F]ASEM; microwave; radiosynthesis; α7-nAChR