Chemical and biological studies on sup(99m)Tc-DMS

Various Tc-dimercaptosuccinate (Tc-DMS) complexes were prepared using both sup(99m)Tc and carrier 99Tc. A yellow complex (Complex I) was obtained at low concentration of Sn(II), and a purple complex (Complex II) with a large excess amount of Sn(II). Potentiometric titration of Sn(II)-DMS indicates the formation of a 1:1 complex alone, which can be utilized as a reducing agent of Tc04-. The absorption spectra suggests that there is little possibility of a mixed metal complex of Tc-Sn-DMS. Potentiometric and radiometric titrations were used for the determination of the technetium valence state. It was found that pertechnetate is reduced to the IV state, which is due to the formation of Complex I. The formation of Complex II is increased as the amount of Sn(II) as well as the molar ratio of Sn(II)/Sn(IV) is increased or the Tc04-concentration decreased. Maximum Complex II formation was observed at the sup(99m)Tc04- only concentration level. Complex II showed the highest kidney uptake, and it is suggested that the Complex II might be a Tc(III)-DMS. (author)