A comparison of F-18 Flortaucipir on different radiosynthesizers: Ora Neptis Perform and GE Tracerlab FXN

1165 Objectives: The Ora Neptis Perform is a radiosynthesizer used in the production of a variety of F-18 based radiotracers via nucleophilic synthesis using single-use disposable plastic cassettes and an integrated semi-prep HPLC system for product purification. The GE Tracerlab FXN is a more common research synthesis unit which contains reusable glass reagent vessels and reactor connected with PTFE tubing and includes an integrated semi-prep HPLC system for product purification, all of which require cleaning after a synthesis. Due to the time needed to thoroughly clean the FXN system, a flexible cassette based automated synthesis unit with a short cleaning and setup time is desired for a high throughput production of F-18 PET radiopharmaceuticals. One of the potential concerns of using a plastic disposable cassette is the effect the plastic cassette would have on chemical purity and specific activity (due to leachable fluorine) on the PET radiopharmaceutical. We chose to compare the two synthesis methods for the production of F-18 Flortaucipir (also known as F-18 AV-1451 and F-18 T807) as a test case. Methods: F-18 Flortaucipir is manufactured using a reactor method with the tBOC precursor dissolved in dimethyl sulfoxide (DMSO) as described in, A concise radiosynthesis of the tau radiopharmaceutical, [18F]T807, T. M. Shoup et al. The synthesis method on the two synthesis platforms was effectively identical, as both used the same reaction, semi-prep HPLC purification and product formulation conditions. The comparison is completed by using the data from several F-18 Flortaucipir production runs using the Ora Neptis Perform and using the past ten production runs on the GE Tracerlab FXN. F-18 was obtained from a GE PETtrace 880 cyclotron by irradiation of O-18 water >98% enrichment. Schematics of each graphic user interface are shown in Figures 1 and 2. The F-18 Flortaucipir product from both the GE Tracerlab FXN and Ora Neptis Perform have the same quality control specifications as detailed in Table 1. Results: The Ora Neptis Perform and the GE Tracerlab FXN are both viable methods for producing F-18 Flortaucipir, as both produce similar results. It was found that the specific activity and product yield at the end of the synthesis is higher on the Neptis Perform synthesizer compared to the Tracerlab FXN. Furthermore, it was determined that the precursor in DMSO was not compatible with the Rotem PC-50 plastic (Polysulfone with HDPE valves) cassettes due to chemical reactivity. Therefore, we tried a DMSO resistant (Tritan mx731 with HDPE valves) manifold in the same configuration as the PC-50 cassette. This method also showed similar results to the GE Tracerlab FXN further making it a viable method for producing F-18 Flortaucipir. All results are shown in Table 1. Conclusions: With some simple modifications such as using a DMSO resistant cassette, the Ora Neptis Perform is an equivalent method, compared to the GE Tracerlab FXN, for the of production of F-18 Flortaucipir. We saw no effect on product yield, chemical purity or specific activity with using the plastic/DMSO resistant cassettes. AcknowledgementsWe thank Tim Beaudoin, Evan Buzgo, John A. Correia, Steven J. Gallo, David F. Lee Jr., Jessica Lee, Tiffany V. L’Heureux, Brian McAvoy, Sung-Hyun Moon, Hamid Sabet, and Danielle Vesper of the Massachusetts General Hospital for isotope production, routine synthesis, quality control and technical support.Keywords Ora Neptis Perform, GE Tracerlab FXN Pro, F-18 Flortaucipir Research Support Shoup TM, Yokell DL, Rice PA, Jackson RN, Livni E, Johnson KA, Brady TJ, Vasdev N. A Concise Radiosynthesis of the Tau Radiopharmaceutical, [18F]T807. J Labelled Comp Radiopharm. 2013, 56, 736-740.