Facile Automated Radiosynthesis of an Arginine Selective Bioconjugation Reagent 4-[¹⁸F]Fluorophenylglyoxal for Developing Protein-Based PET Molecular Probes

4-[¹⁸F]-Fluorophenylglyoxal ([¹⁸F]-FPG) is a novel arginine selective bioconjugation reagent for native protein ¹⁸F-labeling. Here, we report the automated radiosynthesis of [¹⁸F]-FPG on a Scintomics GRP module. The radiochemical preparation was performed in a one-pot, two-step process using a DMSO-resistant cassette system. A cartridge-based purification method was developed to purify [¹⁸F]-FPG without HPLC. The [¹⁸F]-FPG was prepared in nondecay corrected (n.d.c.) radiochemical yields (RCYs) of 27 ± 2% (<i>n</i> = 5) in 56 min from the end of the bombardment until formulation. The molar activities of [¹⁸F]-FPG were 147 ± 70 GBq/μmol (<i>n</i> = 5). The 4-[¹⁸F]-FPG was then conjugated with interleukin-4 (IL-4) in n.d.c. 26 ± 2% RCYs (<i>n</i> = 3) from [¹⁸F]-FPG with molar activities of 24 ± 4 GBq/μmol (<i>n</i> = 3). [¹⁸F]-FPG-IL4 exhibited >95% stability in either PBS (4 h) or human serum (2 h) in vitro. [¹⁸F]-FPG-IL4 showed specific uptake by the PHA-activated Jurkat cells. The in vivo biodistribution and pharmacokinetics of [¹⁸F]-FPG-IL4 were evaluated in healthy Balb/c mice with PET imaging.