Radiolabeling procedure, quality control and stability of 99mTc-labeled chondroitin sulfate: a new approach of targeting osteoarthritis.

Chondroitin sulfate (CS) is an endogenous component of cartilage which could determine osteoarthritis after radiolabeling. Radiolabeling was performed by 99mTcO4−/tin method. We found that pH is a limiting factor. At pH 6.2 in 0.05M Na acetate buffer 32.8% colloid was formed, at pH 5.0 in 0.5M Na acetate, in our methodology only 4.7% colloid. The tracer was highly stable. We conclude that 99mTcCS could be a promising imaging agent of osteoarthritis due to simple radiolabeling and high stability.