Sensitive high-performance liquid chromatographic analysis of amlodipine in human plasma with amperometric detection and a single-step solid-phase sample preparation.

A narrow-bore HPLC assay with electrochemical detection for the determination of the calcium antagonist amlodipine in human plasma samples is presented. By using a single-step solid-phase extraction procedure on Bond Elut C2 columns, the sample preparation step has been considerably simplified and less time-consuming compared to earlier presented works. With a linear and reproducible calibration curve over the range 0.5-20 ng ml-1 plasma, the assay has successfully been used in the analysis of more than 500 plasma samples from a multicenter trial.