6533b851fe1ef96bd12a9730

RESEARCH PRODUCT

Ethanol-Based Post-processing of Generator-Derived 68Ga Toward Kit-Type Preparation of 68Ga-Radiopharmaceuticals

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Post-processing by means of a cation-exchanger–based protocol is an efficient strategy for purification and concentration of generator-derived 68Ga. It ensures the removal of 68Ge before 68Ga-radiopharmaceutical preparation and high labeling yields of 68Ga-labeled radiopharmaceuticals for routine medical application. Methods: In an effort to overcome the problem associated with acetone in the currently applied method, we have investigated the feasibility of replacing it with ethanol. The purification of 68Ga from coeluted metallic impurities (68Ge4+, Fe3+, Zn2+, and Ti4+) on various cation-exchange columns has been investigated with a variety of post-processing solutions. As a proof of principle, the post-processed 68Ga was used to radiolabel DOTATOC in combination with high-purity water and various buffer solutions. Results: An effective protocol for the processing of generator-produced 68Ga on the basis of cation-exchange chromatography using EtOH/HCl medium has been developed. Up to 95% of the initially eluted 68Ga activity can be collected in a 1-mL fraction of 90% EtOH/0.9N HCl after removal of 68Ge-breakthrough in a washing step. The post-processed eluate has been used to radiolabel DOTATOC in yields of approximately 97% ± 0.25% at 80°C in 5 min. Conclusion: The described novel protocol improves the radiolabeling efficiency and efficacy of DOTATOC, providing yields of greater than 99% (decay-corrected). As a result, further purification to separate the desired product from uncomplexed 68Ga is not necessary. The developed post-processing and labeling protocols permit reliable and high-yield preparation of injectable 68Ga-DOTATOC (or other 68Ga-labeled radiopharmaceuticals) that are suitable for routine application. It is possible to incorporate this protocol into existing automated modules.