Abstract:
The preparation of
18F labeled peptides usually needmany reaction steps, long time, harsh reaction conditions, which greatly limitsthe application of
18Flabeled PET probe. Using click chemistry for the synthesis of
18F labeled peptides make thereaction conditions more reliable, efficient and selective. The reactionconditions are mild, low cost, and fast. The purpose of this research was tosynthetize the glycosylated octreotide derivative quickly and easily, todevelop a method of
18Flabeled peptides by click chemistry. We also discussed the exploration of thefeasibility with
18Flabeled glycosylated octreotide derivatives as a somatostatin receptor positivetumor probe. This work prepared 2-
18F-azide ethane precursor compounds by nucleophilic substitution and then labeledPr-Gluc-TOCA by click chemistry, finally we got the product
18F-Ta-Gluc-TOCA by purification.In addition, the in vitro stability and octanolwater partition coefficient of
18F-Ta-Gluc-TOCA were measured.The biodistribution studies of
18F-Ta-Gluc-TOCAin normal mice and tumor bearing nude mice were investigated. The radiochemicalpurity of
18F-Ta-Gluc-TOCAwas 91%. The vitro stability was good. The octanol-water partition coefficientwas -0.43±0.05.The results of biodistribution in normal mice showed rapid clearance fromblood, and excreted mainly through the hepatobiliary metabolism, and also throughthe renal metabolism. The results of the biodistribution in tumor bearing nudemice showed high uptake in the tumor (4.34±0.47%ID/g, 60 min). The findings suggest that
18F-Ta-Gluc-TOCA is a potentialradiotracer for PET imaging of somatostatin receptor positive tumors.