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

The dopamine D2 receptor radiotracer [11C]Raclopride is used extensively in clinical and preclinical imaging. Currently, a wide range of methods to produce [11C]Raclopride have been developed using traditional vessel reactions as well as cartridge or captive solvent. This work reports the optimisation of the production of [11C]Raclopride using a Synthra GPextent, comparing various methods. With optimised conditions, we were able to obtain 4±2% (ndc) yield of [11C]Raclopride (100 GBq [11C]CO2, n = 42) in 25 min. The radiochemical purity was >95% with specific activities of 135±41 MBq/nmol at end of synthesis.