A simplified protocol for the automated production of 2-[18F]fluoro-3-[2-((S)-3-pyrrolinyl)methoxy]pyridine ([18F]nifene) on an IBA Synthera® module

The α4β2 nicotinic acetylcholine receptor (nAChR) ligand 2-[¹⁸F]fluoro-3-[2-((S)-3-pyrrolinyl)methoxy]pyridine ([¹⁸F]nifene) has been synthesized in 10% decay-corrected radiochemical yield using the IBA Synthera® platform (IBA Cyclotron Solutions, Louvain-la-Neuve, Belgium) with an integrated fluidic processor (IFP). Boc-nitronifene served as the precursor, and 20% trifluoroacetic acid (TFA) was used to deprotect the Boc-group after radiolabeling. By omitting the solvent extraction step after radiolabeling, the process was simplified to a single step with no manual intervention. [¹⁸F]Nifene was obtained in decay-corrected radiochemical yields of 10 ± 2% (n = 20) and radiochemical purity >99%. Typical specific radioactivities of 2700–4865 mCi/μmole (100–180 GBq/μmol) were measured at the end of synthesis; total synthesis times were about 1 h 40 min.