ABSTRACT
Objective To synthesize 18F labeled N-(2-18 F-fluoropropionyl)-L-glutamine (18 F-FPGLN) for tumor PET imaging,and to perform its biodistribution study on normal mice and PC-3 tumorbearing nude mice.Methods 4-nitrophenyl-2-18F-fluoropropionate (18F-NFP) was synthesized on the MF2V-IT-I synthesizer and was purified by semi-preparative HPLC.Anhydrous 18F-NFP was added to a solution of L-glutanine t-butyl ester to synthesize 18F-FPGLN t-butyl ester,which was hydrolyzed by HCl (3 mol/L) and neutralized with NaOH (2 mol/L) solution.18F-FPGLN product was collected for further study.Biodistribution study was performed on normal Kunming mice and PC-3 prostate cancer tumor-bearing nude mice,respectively.Results 18F-FPGLN was synthesized with 10％-15％ (decay uncorrected) overall radiochemical yield after 130 min of radiosynthesis.The radiochemical purity was higher than 96％.Rapid and high uptake of radiotracer was observed within the kidneys,and was quickly excreted through the urinary bladder.The uptake in kidney reached (35.0±1.2) ％ID/g at 5 min post-injection,and descended to (1.5±0.3) ％ID/g at 120 min.The liver,lung,heart and small intestine showed relatively moderate uptake of radioactivity.The uptake in the pancreas,muscle,spleen,stomach and brain was low,and the lowest uptake of (1.5±0.3) ％ID/g was found in the brain at 30 min post injection.High accumulation of 18F-FPGLN in PC-3 xenograft was observed,and the tumor/muscle ratio reached 2.07 at 60 min post injection.Conclusion A novel N-position 18F-labeled glutamine analogs 18F-FPGLN,with favorable pharmacokinetic characteristics,is synthesized successfully,which makes it possible to perform tumor PET imaging using 18F-FPGLN subsequently.