18F-Fluoroglucosylation of an arginine-arginineleucine peptide as a potential tumor imaging agent for positron emission tomography

Background: based on the principle of oxime formation, 18f labeling of polypeptides can be achieved via a reaction between an aldehyde groupcontaining 18f-prosthetic group and an aminooxy-modified polypeptide. the focus of this study was to investigate the one-step synthesis of 2-[18f] fluoro-2 -deoxyglucose (18f-fdg)- arginine-arginine-leucine (rrl) from open-ring 18ffdg and the aminooxy-modified rrl peptide cyclo(rrlfk)-onh2 and to study the biological distribution of 18f-fdg-rrl in a nude mouse model of human neuroglioma. materials and methods: the aminooxy-modified rrl peptide cyclo(rrlfk)-onh2 was used as the precursor to react with 18f-fdg at 100 ℃ and different ph values for 30 minutes to synthesize 18f-fdg-rrl. the labeling yield, radiochemical purity, and in-vitro stability of the product were measured, and the biological distribution of 18f-fdg-rrl in tumor-bearing nude mice was analyzed at 30 minutes, 60 minutes and 120 minutes. results: the labeling yield of 18f-fdg-rrl was (25.5±5.0) % at a ph of 2.0, and its radiochemical purity was greater than 95%. 18f-fdg-rrl was mainly excreted through the kidneys, with rapid blood clearance. one hour after injection, the uptake of 18f-fdg-rrl in tumors was (1.83±0.12) injected dose per gram of tissue (%id/g), with a tumor/muscle ratio of 7.03±0.04, a tumor/blood ratio of 4.36±0.21 and a tumor/brain ratio of 7.53±1.37. conclusion: the synthesis of 18f-fdg-rrl can be achieved through oximation. this method is straightforward and easy to promote. 18f-fdg-rrl has rapid blood clearance and high uptake by tumors.