Automated purification system based on disposable kits for the separation of ^99mTc from solutions with high molybdate content

Objectives Most alternative production methods used to make ^99mTc, such as the ¹⁰⁰Mo(p,2n)^99mTc reaction, lead to solutions containing an excess of molybdate that cannot be effectively trapped on a small alumina cartridge. We report the development of a kit-based system that is suitable for good manufacturing practice (GMP) purification of ^99mTc from solutions with high molybdate content.

Methods We used the Trasis Mini AIO synthesizer to implement a ^99mTcO₄^- purification system for cyclotron production of ^99mTc. The system is based on two-phase partitioning using crosslinked PEG resins (Chemmatrix). The first step involved trapping of ^99mTc on the Chemmatrix resin, followed by elution with water. The water solution was passed through a cation exchange resin and a small alumina column to remove potential traces of molybdate. The final product was eluted in 10 mL of 0.9% NaCl. Solutions containing ^99mTc, 4M NaOH and 1.5 g of molybdenum metal dissolved in H₂O₂ were tested. All components were made of USP class VI plastics, were available at low cost, and were fully disposable. The system was designed to enable recovery of molybdate for recycling to make new cyclotron targets or reuse as a generator system.

Results The system was highly efficient at recovering ^99mTc within minutes, with a recovery rate of 91.7 ± 3.6% (mean ± st. dev.). Minimal losses were due to activity that was not trapped (1.2 ± 0.7%) or remained on the resin (4.8 ± 3.7%), the final alumina column (0.9 ± 0.3%) or other kit components (1.9 ± 1.0 %).

Conclusions ^99mTc-pertechnetate can be purified in high yields from solutions with a high molybdate content using a simple disposable kit system that is suitable for GMP manufacturing.

Research Support Natural Resources Canada