Reliable One-Pot Automated Preparation of [¹¹C]SL25.1188 for Use in Clinical Imaging Studies

We clinically investigated (S)-5-methoxymethyl-3-[6-(4,4,4-trifluorobutoxy)benzo[d]isoxazol-3-yl]oxazolidin-2-[¹¹C]-one ([¹¹C]SL25.1188) as a positron emission tomography tracer for imaging monoamine oxidase B. To perform clinical imaging studies at our institute, we established a routine method for preparing the [¹¹C]SL25.1188 injection using a one-pot [¹¹C]CO₂ fixation method. We successfully prepared the [¹¹C]SL25.1188 injection using a ¹¹C-labeling synthesizer and sterile isolator. The radiosynthesis time and decay-corrected radiochemical yield based on [¹¹C]CO₂ were below 30 min and 49% ± 10% postirradiation (n = 104), respectively. At the end of synthesis (n = 104), the molar activity was 180 ± 57 GBq/μmol, and the radiochemical purity exceeded 99%. The results of [¹¹C]SL25.1188 injection complied fully with our in-house quality control and quality assurance criteria, confirming a reliable supply of high-quality [¹¹C]SL25.1188 formulation with adequate radioactivity for use in clinical imaging studies.