Comparative examinations of 99mTc-DMS preparations obtained by labelling dimercaptosuccinate kits with different formulations. II. Comparison of chemical and biological characteristics of TcP-5 and MPI kits.

The chemical and biological characteristics of two dimercaptosuccinate kits were examined and compared: TcP-5 (produced at the Boris Kidric Institute - Vinca) in the freeze-dried form and MPI - the aqueous solution of tin dimercaptosuccinate. The radiochemical composition of the injection solutions was examined by various methods and the method of ascending paper chromatography in 50% aqueous methanol was found as satisfactory. Both preparations has similar compositions. Both preparations showed maximum renal concentrations 3-4 hrs after injection. Liver uptake of MPI was higher than that of TcP-5. The bench-life of both preparations was compared by measuring organ distribution. TcP-5 had a bench-life at least six hrs with a kidney/liver uptake ratio from 5.60 to 8.52, whereas MPI had a satisfactory bench-life of less than half an hour after labelling; thereafter, hepatic concentration rose and the kidney/liver uptake ratio dropped to 1.64.