Automatic synthesis and quality control of ¹¹C-Raclopride for clinical use

Abstract: Automatic synthesis of ¹¹C-Raclopride was used for routinely clinical imaging with home-made C-11 synthesized module. METHODS: ¹¹C-Triflate-CH₃ was bubbled through a vial at room temperature, containing a acetone solution of precursor and NaOH. The reaction solution was transferred to Semi-HPLC for purification. The crude production was purified by C-18 Solid-Extraction-Purification (SEP). The injection solution was formatted by 1 mL alcohol eluated from the SEP-C-18, the eluated soluation was diluted with saline to less 10% of alcohol. RESULTE: The amount of base leaded to increase the yields of by-production of C-N methlyation. The synthesis yield was (55.1 ± 8.4)% (n = 40) with precursor of 0.1 to 0.4 mg, and had no relationship with NaOH in 1 μmol to 50 μmol. It took 28 min from ¹¹CO₂ to obtain ¹¹C-Raclopride injection solution. The radiochemical purity was over 99%. The radiochemical concentration was 370 to 550 MBq/mL at specific activity of 1.73 × 10¹⁴ Bq/g. The injection solution was proved to be sterile and pyrogen free. CONCLUSION: ¹¹C-Raclopride was automatic synthesized from ¹¹CH₃-Triflate with home-made C-11 synthesizer module. The quality and quantity of ¹¹C-Raclopride injection solution was confirmed to be suitable for clinical PET imaging. (authors)