Preparation of a chemically characterized 99mTc-penicillamine complex.

In the reaction labeling penicillamine with 99mTc, serveral different chemical states of 99mTc were observed to occur with slight changes in the labeling conditions, such as the concentrations of penicillamine, 99mTcO4-, stannous chloride, and hydrogen ion. We have studied the effects of these conditions on the formation of the monomer complex that we call Complex I, in which 99mTc is coordinated with the penicillamine as 99mTcO+2. Our approach is based on the thesis that Complex I formation competes with 99mTcO+2 hydrolysis, which leads to other 99mTc complexes. On this basis, the specific labeling conditions for Complex I formation have been established. Highly reproducible in vivo behavior in mice and rats was obtained with this chemically controlled Complex I.