Large-Scale Production of ^119mTe and ¹¹⁹Sb for Radiopharmaceutical Applications

Abstract

Radionuclides find widespread use in medical technologies for treating and diagnosing disease. Among successful and emerging radiotherapeutics, ¹¹⁹Sb has unique potential in targeted therapeutic applications for low-energy electron-emitting isotopes. Unfortunately, developing ¹¹⁹Sb-based drugs has been slow in comparison to other radionuclides, primarily due to limited accessibility. Herein is a production method that overcomes this challenge and expands the available time for large-scale distribution and use. Our approach exploits high flux and fluence from high-energy proton sources to produce longer lived ^119mTe. This parent isotope slowly decays to ¹¹⁹Sb, which in turn provides access to ¹¹⁹Sb for longer time periods (in comparison to direct ¹¹⁹Sb production routes). We contribute the target design, irradiation conditions, and a rapid procedure for isolating the ^119mTe/¹¹⁹Sb pair. To guide process development and to understand why the procedure was successful, we characterized the Te/Sb separation using Te and Sb K-edge X-ray absorption spectroscopy. The procedure provides low-volume aqueous solutions that have high ^119mTe-and consequently ¹¹⁹Sb-specific activity in a chemically pure form. This procedure has been demonstrated at large-scale (production-sized, Ci quantities), and the product has potential to meet stringent Food and Drug Administration requirements for a ^119mTe/¹¹⁹Sb active pharmaceutical ingredient.