Validation of a capillary electrophoresis assay for assessing the metabolic stability of verapamil in human liver microsomes.

A simple CE assay for the rapid determination of the in vitro metabolic stability of verapamil in human liver microsomes has been developed and validated. Verapamil was used as the prototype drug since it is extensively metabolized in human liver microsomes. The assay showed good intra- (CV < or = 10%) and interday (CV < or = 8%) reproducibility. The recovery of verapamil after incubation at 37 degrees C for 60 min with human liver microsomes was low (15 +/- 1%) and two metabolites were detected. The method is currently in use for assessing the metabolic stability of new drug candidates at an early stage of lead optimization at Cardiome Pharma Corp. (Vancouver, BC, Canada).