Synthesis of ¹¹C-CIC for PET Imaging of Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory neurodegenerative disorder of central nervous system. Imaging of myelin tracts in vivo would greatly improve the diagnosis and monitoring of MS. The ¹¹C-CIC was synthesized with ¹¹C-CH₃-Triflate at high yields, and was confirmed by biodistribution and imaging. ¹¹C-CH₃-Triflate was distilled and trapped into a reaction vial containing the 2 mg precursor. The final production was purified by semi-HPLC to get ¹¹C-CIC. The in vitro stability of ¹¹C-CIC was studied at RT with or without Vc. The normal NH mice were sacrificed at different time after injection of ¹¹C-CIC for biodistribution. The micro PET/CT was performed at 30 min post-injection. The radiochemical yield was 55%65% decay corrected to ¹¹CH₃-Triflate. The radiochemical purity was over 99% at specific activity of 60 GBq/μmoL. The HPLC showed the poor stability of ¹¹C-CIC in vitro. The ¹¹C-CIC was very stable after the 10 g/L Vc used as stabilizer. The initial uptake of the cerebrum was 2.78%ID/g. The radioactivity were excreted from the digestive system and urine. The micro PET/CT imaging showed good uptake in the cerebrum. The stability of ¹¹C-CIC can be improved with Vc as stabilizer. The¹¹C-CIC was a candidate for imaging of myelin tracts for diagnosis or monitor MS.