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Radiosynthesis of [ 18 F]PBR111, a selective radioligand for imaging the translocator protein (18 kDa) with PET
Author(s) -
Dollé Frédéric,
Hinnen Françoise,
Damont Annelaure,
Kuhnast Bertrand,
Fookes Christopher,
Pham Tien,
Tavitian Bertrand,
Katsifis Andrew
Publication year - 2008
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.1559
Subject(s) - chemistry , radiosynthesis , radioligand , translocator protein , high performance liquid chromatography , specific activity , radiochemistry , ligand (biochemistry) , reagent , nucleophile , pet imaging , nucleophilic substitution , labelling , nuclear chemistry , chromatography , positron emission tomography , medicinal chemistry , nuclear medicine , receptor , organic chemistry , enzyme , medicine , biochemistry , neuroinflammation , inflammation , catalysis
PBR111 (2‐(6‐chloro‐2‐(4‐(3‐fluoropropoxy)phenyl)imidazo[1,2‐ a ]pyridin‐3‐yl)‐ N , N ‐diethylacetamide) is a novel, reported, high‐affinity and selective ligand for the translocator protein (18 kDa). PBR111 has been labelled with fluorine‐18 (half‐life: 109.8 min) using our Zymate‐XP robotic system. The process involves (A) a simple one‐step tosyloxy‐for‐fluorine nucleophilic aliphatic substitution (performed at 165°C for 5 min in DMSO using K[ 18 F]F‐Kryptofix ® 222 and 6.8–7.6 µmol of the corresponding tosylate as precursor for labelling) followed by (B) C‐18 PrepSep cartridge pre‐purification and (C) semi‐preparative HPLC purification on a Waters Symmetry ® C‐18. Up to 4.8 GBq (130 mCi) of [ 18 F]PBR111 could be obtained with specific radioactivities ranging from 74 to 148 GBq/µmol (2–4 Ci/µmol) in 75–80 min (HPLC purification and SepPak ® ‐based formulation included), starting from a 37.0 GBq (1.0 Ci) [ 18 F]fluoride batch. Overall non‐decay‐corrected isolated yields were 8–13% (13–21% decay‐corrected). Copyright © 2008 John Wiley & Sons, Ltd.