ELECTROCHEMICAL PREPARATION OF TECHNETIUM HYDROXYETHYLIDENE DIPHOSPHONATE RADIOPHARMACEUTICALS (HPLC).

摘要

This work describes the liquid chromatographic and electrochemical analysis of electrogenerated technetium hydroxyethylidene diphosphonate (HEDP) complexes, and studies the effectiveness of the resulting bone imaging agents.;Anion exchange High Performance Liquid Chromatography is used to separate components, and gamma emission is used as the detection mode. The reaction mixtures were prepared at a series of reduction potentials and pH values, at both "carrier added" and "no carrier added" technetium levels. The results indicate that all three parameters affect the final complex composition to varying degrees.;By optimizing the conditions, a preparation was made which results in a high percentage of a Tc-HEDP complex thought to be a very good home imager. This component was isolated chromatographically and injected into female Sprague-Dawley rats. Comparisons were run on the uptake for seven tissue types at two incubation times. This data verifies the suspected high quality imaging capability of the electrochemically reduced preparation. Mercury and Reticulated Vitreous Carbon were used as the working electrode materials, and it is shown how reduced technetium will significantly alter the electrode characteristics, where a conditioned electrode will produce different complexes from those produced at fresh electrode material.;By employing coulometric analysis as the preparation was reduced, an n value of 4 was calculated for a particular complex. This procedure involved tracking the radioactive technetium species carefully to account for all electrons used in the system. The resulting Tc (III) species is in good agreement with literature postulations.;The digital coulometer used in this work was constructed in-house, and is also characterized and tested herein.;Finally, an electrochemical detection method for HEDP was explored, utilizing the property of mercury complexation. Anodic sweep Differential Pulse Polarography gives an analytical signal for HEDP at +0.250 V vs Ag/AgCl.