COMPARISON OF REVERSED-PHASE AND REVERSED-PHASE ION-PAIR HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY FOR ANALYSIS OF TCO AND TCN COMPLEXES OF L,L-ETHYLENE DICYSTEINE DI-ETHYLESTER AND ITS ACID ANALOGS

Tc-99m(V)-oxo complexes of L,L-ethylene dicysteine (L,L-EC) and its di -ester derivative L,L-ethyl cysteinate dimer (L,L-ECD) are useful trac er agents for evaluation of renal function and cerebral blood flow res pectively. Labelling of these molecules with a Tc-99m(V)-nitrido core instead of the Tc-99m(V)-oxo core alters their biological and physioch emical behaviour. In the reversed phase high performance liquid chroma tography (HPLC) method presently used to analyse Tc-99m(V)-oxo prepara tions of L,L-EC and L,L-ECD, the Tc-99m(V)-nitrido-L,L-EC complex and the possible impurities of a Tc-99m(V)-nitrido-L,L-ECD preparation wer e found to elute with the void volume. In this study, a reversed phase ion pair HPLC method has been developed that is useful for the analys is of both Tc-99m(V)-oxo and Tc-99m(V)-nitrido preparations of L,L-EC and L,L-ECD. Tetrabutylammonium hydroxide is used as a cationic ion pa iring agent.