Frederick T. Chin, Ph.D.

Automated radiosynthesis of [18F]SPA-RQ for imaging human brain NK1 receptors with PET

Chin FT, Morse CL, Pike VW.. Journal of Labelled Compounds and Radiopharmaceuticals. 2006; 49 (1): 17-31

[18F]SPA-RQ is an effective radioligand for imaging brain neurokinin type-1 (NK1) receptors in clinical research and drug discovery with positron emission tomography. For the automated regular production of [18F]SPA-RQ for clinical use in the USA under an IND we chose to use a modified commercial synthesis module (TRACERlab FXF-N; GE Medical Systems) with an auxiliary custom-made robotic cooling-heating reactor, after evaluating several alternative radiosynthesis conditions. The automated radiosynthesis and its quality control are described here. [18F]SPA-RQ was regularly obtained within 150 min from the start of radiosynthesis in high radiochemical purity (>99%) and chemical purity and with an overall decay-corrected radiochemical yield of 15±2% (mean±S.D.; n=10) from cyclotron-produced [18F]fluoride ion. The specific radioactivity of [18F]SPA-RQ at the end of synthesis ranged from 644 to 2140 mCi/µmol (23.8-79.2 GBq/µmol).