Optimisation of [C-11] Raclopride Production Using a Synthra GPextent System

The dopamine D-2 receptor radiotracer [C-11]Raclopride is used extensively in clinical and preclinical imaging. Currently, a wide range of methods to produce [C-11]Raclopride have been developed using traditional vessel reactions as well as cartridge or captive solvent. This work reports the optimisation of the production of [C-11]Raclopride using a Synthra GPextent, comparing various methods. With optimised conditions, we were able to obtain 4 +/- 2% (ndc) yield of [C-11]Raclopride (100 GBq [C-11]CO2, n = 42) in 25 min. The radiochemical purity was >95% with specific activities of 135 +/- 41 MBq/nmol at end of synthesis.