Preparation and stability evaluation of small interference RNA radiolabeled with 99Tcm

This study was to develop an available method of radiolabeling siRNA via conjugation with chelator of S-acetyl NHS-MAG3, and to evaluate its radiolabeled efficiency and stability in vitro. At room temperature, the labeling efficiency reaches (73.4±3.0)% under the reaction condition of reaction time above 1 h, and ρ (SnCl2·2H2O)<2 g/L. After Sephadex G25 purification, the radiochemical purity is no less than 92% and the specific activity is up to 25.9 PBq/mol. In different mediums of saline and fresh human serum, the radiochemical purity keeps high stability in room temperature and 37 degree C. 99Tcm-labeled siRNA has the same targeted inhibition activity as non-labeled siRNA. (authors)