An improved method for the preparation of [11C]verapamil

This paper describes an improved preparation of [11C]verapamil by reaction of [11C]methyl triflate with desmethylverapamil. The optimal reaction temperature, amount of precursor and reaction time were assessed. With this method [11C]verapamil can be prepared with a reproducible radiochemical yield of 66±4% (EOB, based on [11C]methyltriflate). Total synthesis time was 60 min. Radiochemical purity was >99% and specific activities varied between 5 and 30 TBq/mmol.