Determination of dynamic dissociation constant of chromium-poly(N-vinylpyrrolidone)complex by the radiotracer technique

摘要

The binding ability of polyvinylpyrrolidone (PVP) with chromium in its different oxidation states has been investigated. The complexation of PVP towards Cr(III) and Cr(VI) labeled with ~(51)Cr radionuclide has been studied with the dialysis" technique. The stability of the complexes has been examined by measuring the dynamic dissociation constant from the slope of the plot of ln{Cr(VI)/(III)-PVP} versus time. It has been observed that both Cr(VI)-PVP and Cr(lII)-PVP complexes are most stable at pH 7. However, the Cr(IlI)-PVP complex is more stable than the Cr(VI)-PVP complex at all pH values. This study shows the comparative stability of the complexes of the two different species of chromium with PVP, which may be useful in radiopharmaceutical sciences.