Sep pak light qma

All chemicals used in the synthesis were commercially sourced and used without further purification unless otherwise indicated. [¹⁸F]FDG was radiolabeled as previously described (Luo et al., 2009 (link)). Sep-Pak light QMA and Plus C18 cartridges were purchased from Waters Corporation (Milford, MA, USA). Sep-Pak light QMA cartridges were preconditioned with 10 ml of NaHCO₃ aqueous (8.4%) and water in advance. Preconditioning of the Plus C18 cartridge was performed with 10 ml of ethanol followed by 10 ml of water. A micro PET/CT scanner by Siemens Healthineers (Erlangen, Germany) was used.

The commercial ¹⁸F ion was produced by SUMITOMO cyclotron (HM-7, Sumitomo Heavy Industry, Tokyo, Japan). Radio-synthesis of [¹⁸F]FDG was performed as classic studies [22 (link)]. The radiolabeling process of [¹⁸F]DPA714 was similar to the reported protocol in literature [23 (link)]. Simply, ¹⁸F ion was first captured by QMA column (Sep-Pak® Light QMA, Waters Corporation, Milford, Massachusetts USA), then eluted into the reaction tube with K22/K₂CO₃ solution, and added with 2 mL of anhydrous acetonitrile. Following azeotropic water removal, the reaction system was cooled to room temperature after completion. Next, add 1 mL of DPA714 precursor dissolved in anhydrous acetonitrile to the reaction tube, and raise the temperature to 100°C for fluorination reaction for 10 min, and cool the system to room temperature after reaction. Then, add 10 mL of water to dilute the reaction system, inject the diluted solution to C18-column for separation, wash the column with 20 mL of water, and elute the labelled product with 1 mL of anhydrous ethanol. Take a portion of the radiolabeled product for identification and preparation purity assay by preparative HPLC, with [¹⁹F]DPA714 as the standard reference, and collect the target peak. The final radiochemical purities of products [¹⁸F]FDG and [¹⁸F]DPA714 were both >95%.

All commercially available materials were used without further purification. The d-Lys⁶-GnRH [(Glp)-HWSY(D)KLRPG-NH₂], [His⁵, d-Tyr⁶]GnRH [(Glp)-HWSH(D)YLRPG-NH₂], and NOTA-P-d-Lys⁶-GnRH (P = PEG₃) were custom manufactured from GL Biochem Ltd. (Shanghai, China). Sep-Pak light QMA and Plus C18 cartridges were obtained from Waters Corporation (Milford, MA, USA). High-performance liquid chromatography (HPLC) separation was performed on the PET-MF-2V-IT-I synthesizer module (PET Co. Ltd., Beijing, China) built-in HPLC system with a semipreparative reverse-phase C18 column (10 × 250 mm). Analytical HPLC was performed using a LC-20AD HPLC system (Shimadzu, Japan) equipped with a ZORBAX Eclipse XDB-C18 analytic column (4.6 × 150 mm, 5 μm; Agilent Technologies, USA). Radioactivity was measured by a calibrated ion chamber (Capintec CRC-15R, Capintec, Inc. NJ, USA) or a gamma counter (γ-counter) (CAPRAC-R, Capintec, Inc. NJ, USA). High-resolution mass spectra were recorded with a Thermo Fisher Scientific Orbitrap Fusion mass spectrometer. No-carrier-added ¹⁸F-fluoride was obtained by reacting ¹⁸O(p, n)¹⁸F in a GE PET trace cyclotron with irradiating enriched [¹⁸O]water (98%). Statistical analysis was performed using Microsoft Office Excel. Continuous variables were analyzed using the Student's t-test with a significance level of P value less than 0.05.

Syntheses of the precursor to 9-(+)-¹¹C-DTBZ were purchased from ABX. The precursor of 10-(+)-¹¹C-DTBZ was synthesized according to Freyberg et al and can yield this precursor after hydrolysis [29 (link)]. (+)-DTBZ was prepared by reducing and demethylating tetrabenazine (TBZ) to obtain (+)-9-O-desmethyl-DTBZ or (+)-10-O-desmethyl-DTBZ. TBZ derivatives (Fig 1) were synthesized in the laboratory of the School of Pharmacy (National Taiwan University, Taipei, Taiwan). Sodium hydroxide was purchased from Sigma-Aldrich (St. Louis, MO, USA). Trifluoroacetic acid was purchased from Alfa Aesar (Ward Hill, MA, USA). Analytical reagent-grade reagents and solvents were purchased from Aldrich or Merck. The tC₁₈ Sep-Pak and Sep-Pak Light QMA cartridges were acquired from Waters Chromatography Division, Millipore Corporation.
HPLC analysis was performed with a Waters HPLC system equipped with both UV (280 nm) and radioactivity detectors.