Synthesis of 6-[¹⁸F]fluoro-PBR28, a novel radiotracer for imaging the TSPO 18 kDa with PET.

6-Fluoro-PBR28 (N-(6-fluoro-4-phenoxypyridin-3-yl)-N-(2-methoxybenzyl)acetamide), a fluorinated analogue of the recently developed TSPO 18 kDa ligand PBR28, was synthesized and labelled with fluorine-18. 6-Fluoro-PBR28 and its 6-chloro/6-bromo counterparts were synthesized in six chemical steps and obtained in 16%, 10% and 19% overall yields, respectively. Labelling with fluorine-18 was performed in one single step (chlorine/bromine-for-fluorine heteroaromatic substitution) using a Zymate-XP robotic system affording HPLC-purified, ready-to-inject, 6-[(18)F]fluoro-PBR28 (>95% radiochemically pure). Non-decay-corrected overall yields were 9-10% and specific radioactivities ranged from 74 to 148 GBq/μmol. In vitro binding experiments, dynamic μPET studies performed in a rat model of acute neuroinflammation (unilaterally, AMPA-induced, striatum-lesioned rats) and ex vivo autoradiography on the same model demonstrated the potential of 6-[(18)F]fluoro-PBR28 to image the TSPO 18 kDa using PET.

Damont A ，Boisgard R ，Kuhnast B ，Lemée F ，Raggiri G ，Scarf AM ，Da Pozzo E ，Selleri S ，Martini C ，Tavitian B ，Kassiou M ，Dollé F ... -  《-》

[(18)F]Fluoromethyl-PBR28 as a potential radiotracer for TSPO: preclinical comparison with [(11)C]PBR28 in a rat model of neuroinflammation.

Moon BS ，Kim BS ，Park C ，Jung JH ，Lee YW ，Lee HY ，Chi DY ，Lee BC ，Kim SE ... -  《-》

Synthesis of [11C]FEDAA1106 as a new PET imaging probe of peripheral benzodiazepine receptor expression.

Wang M ，Gao M ，Hutchins GD ，Zheng QH ... -  《-》

Fully automated radiosynthesis of [¹¹C]PBR28, a radiopharmaceutical for the translocator protein (TSPO) 18 kDa, using a GE TRACERlab FXC-Pro.

In order to image the translocator protein (TSPO) 18kDa in the clinic using positron emission tomography (PET) imaging, we had a cause to prepare [(11)C]PBR28. In this communication we highlight our novel, recently developed, one-pot synthesis of the desmethyl-PBR28 precursor, as well as present an optimized fully automated preparation of [(11)C]PBR28 using a GE TRACERlab FX(C-Pro). Following radiolabelling, purification is achieved by HPLC and, to the best of our knowledge, the first reported example of reconstituting [(11)C]PBR28 into ethanolic saline using solid-phase extraction (SPE). This procedure is operationally simple, and provides high quality doses of [(11)C]PBR28 suitable for use in clinical PET imaging studies. Typical radiochemical yield using the optimized method is 3.6% yield (EOS, n=3), radiochemical and chemical purity are consistently >99%, and specific activities are 14,523Ci/mmol.

Hoareau R ，Shao X ，Henderson BD ，Scott PJ ... -  《-》

Design and synthesis of a new [18F]fluoropyridine-based haloacetamide reagent for the labeling of oligonucleotides: 2-bromo-N-[3-(2-[18F]fluoropyridin-3-yloxy)propyl]acetamide.

Kuhnast B ，de Bruin B ，Hinnen F ，Tavitian B ，Dollé F ... -  《BIOCONJUGATE CHEMISTRY》