Recent Advances in Technetium Chemistry: Bridging Inorganic Chemistry and Nuclear Medicine

HPLC separated fractions of 99mTc(NaBH4)-HEDP as myocardial infarct imaging agents

Component fractions of 99mTc(NaBH4)-HEDP mixtures, isolated by anion exchange high performance liquid chromatography (HPLC), have been evaluated as myocardial infarct imaging agents in two animal models. Results from both the isoproterenol-induced myocardial infarction model, and the heat-induced myocardial necrosis model, show that the several HPLC isolated components exhibit significantly different abnormal/normal heart uptake ratios. In addition, the HPLC isolated component of shortest chromatographic retention time exhibits a higher abnormal/normal heart uptake ratio than does 99mTc(Sn)-PyP, the current agent of choice for clinical myocardial infarct imaging.

Characterization of technetium radiopharmaceuticals by thin-layer spectroelectrochemistry

Optically transparent thin-layer electrode (OTTLE) techniques have been used to characterize technetium complexes of biomedical importance. Different Tc oxidation states have been generated at the electrodes and absorption spectra determined. Small cell volumes allow the study of materials available in small quantities, and a flow cell configuration has also been used. Heart and bone imaging agents have been studied.

The effect of formulation conditions on the distribution of 99mTc(NaBH4)-HEDP components separated by anion exchange HPLC

Reduction of 99mTcO4- by NaBH4 in the presence of HEDP leads to a mixture of 99mTc-containing complexes which can be separated by anion exchange high performance liquid chromatography (HPLC). The distribution of complexes within this mixture can be varied by controlling pH, the concentration of HEDP, the concentration of technetium, and the presence of air. Suitable control of these formulation conditions can yield mixtures which consist of essentially (greater than 85%) one component. Arguments are presented to support the view that the components of 99mTc(NaBH4)-HEDP and 99mTc(NaBH4)-MDP mixtures are in fact oligomeric or polymeric complexes that can contain technetium centers in at least two different oxidation states.