Automated synthesis of [68Ga]Ga-FAPI-46 without pre-purification of the generator eluate on three common synthesis modules and two generator types
Ammar Alfteimi, Ulf Lützen, Alexander Helm, Michael Jüptner, Marlies Marx, Yi Zhao, Maaz Zuhayra
Abstract
Abstract Background The recent development of quinoline-based radiotracers, which act as fibroblast activation protein inhibitors (FAPIs), has shown promising preclinical and clinical advantages. [ 68 Ga]Ga-FAPI-46 is a new radiotracer for in vivo detection of the fibroblast activation protein by positron emission tomography (PET). Recently, the automated synthesis of [ 68 Ga]Ga-FAPI-46 was reported based on pre-concentration and purification of the generator eluate by using a cation exchange-cartridge. Our aim was to simplify the synthesis and shorten the automated synthesis of [ 68 Ga]Ga-FAPI-46 to make it accessible and thus even more attractive to a broader clinical and scientific community. Results We developed and evaluated the GMP compliant automatic synthesis of [ 68 Ga]Ga-FAPI-46 using two different 68 Ge/ 68 Ga generators (an Eckert & Ziegler, GalliaPharm generator, 1.85 GBq/50 mCi and an iThemba generator, 1.85 GBq/50 mCi) Somerset West, South Africa) and three different commercial and customized systems: the EasyOne module from Trasis; the GaSy module from Synthra with a customized synthesis template and a customized single use cassette. Additionally, the automatic synthesis of [ 68 Ga]Ga-FAPI-46 was established on a GallElut synthesis module from Scintomics with fixed tubing. Conclusions Independent of the synthesis modules or the generators employed we were able to complete the synthesis of [ 68 Ga]Ga-FAPI-46 in 12 min including the process of purification and formulation. In all cases, the final products showed more than 99.5% chemical purity and the radiochemical yield reached around 92.5% (decay corrected). All quality control parameters (e.g. sterility, stability and radiochemical purity) were conform to the European Pharmacopoeia.