Automated synthesis of N-(2-[ F]Fluoropropionyl)-l-glutamic acid as an amino acid tracer for tumor imaging on a modified [ F]FDG synthesis module.

N-(2-[ F]Fluoropropionyl)-l-glutamic acid ([ F]FPGLU) is a potential amino acid tracer for tumor imaging with positron emission tomography. However, due to the complicated multistep synthesis, the routine production of [ F]FPGLU presents many challenging laboratory requirements. To simplify the synthesis process of this interesting radiopharmaceutical, an efficient automated synthesis of [ F]FPGLU was performed on a modified commercial fluorodeoxyglucose synthesizer via a 2-step on-column hydrolysis procedure, including F-fluorination and on-column hydrolysis reaction. [ F]FPGLU was synthesized in 12 ± 2% (n = 10, uncorrected) radiochemical yield based on [ F]fluoride using the tosylated precursor 2. The radiochemical purity was ≥98%, and the overall synthesis time was 35 minutes. To further optimize the radiosynthesis conditions of [ F]FPGLU, a brominated precursor 3 was also used for the preparation of [ F]FPGLU, and the improved radiochemical yield was up to 20 ± 3% (n = 10, uncorrected) in 35 minutes. Moreover, all these results were achieved using the similar on-column hydrolysis procedure on the modified fluorodeoxyglucose synthesis module.