Synthesis of 99mTc-Radiolabeled Uridine as a Potential Tumor Imaging Agent

Abstract

Uridine, a pyrimidine nucleoside essential for the synthesis of RNA and biomembranes, was radiolabeled with ^99mTc to obtain a potential tumor imaging agent. The maximal radiochemical yield of about 96.5%, as determined by paper chromatography and instant thin-layer chromatography, was reached under the following optimum conditions: 1 mg of uridine, 20 μg of SnCl₂·2H₂O as reducing agent, 20 mg of mannitol as a stabilizer, and pH 8. ^99mTc-uridine is stable in vitro at room temperature for up to 6 h post labeling. The biodistrbution study in tumor-bearing mice shows high target-to-nontarget ratio. These results match with the high docking score of the complex on uridine phosphorylase enzyme. ^99mTc-uridine shows promise as a tumor imaging agent.