Labeling of chondroitin sulfate with 99Tcm and its biodistribution in mice

The feasibility of direct labeling of chondroitin sulfate (CS) with 99Tcm was studied, and the effects of different conditions on labeling yield was observed, the biodistribution of 99Tcm-CS in normal mice was investigated, chondroitin sulfate was labeled directly with 99Tcm reduction of 99TcmO4 with SnCl2 solution. The labeling yield and radiochemical purity were determined with thin layer chromatography (TLC) using Xinhua filter paper. The biodistribution of 99Tcm-CS in normal mice was studied at 30 min, 1, 2, 4 and 8 h respectively after caudal vein injection in normal mice. The labeling yield was 81.6% ± 1.7% and radiochemical purity was 90.1% ± 1.2% after filtering by micropore membrane. The biodistribution in mice showed that 99Tcm-CS was cleaned out from blood quickly, and it was mainly excreted through kidney, but 99Tcm-CS had high specificity to cartilage, its uptake ratio of target and nontarget was high, the uptake ratio of cartilage to blood was 8.31 (4 h), the ratio of cartilage to bone was 2.03 (4 h). 99Tcm-CS is an easily prepared and labeled compound with high philo-cartilage and stability. (authors)