High-performance liquid chromatographic determination of the H+/K+ ATPase inhibitor (BY 1023/SK&F 96,022) and its sulphone metabolite in serum or plasma by direct injection and fully automated pre-column sample clean-up.

A fully automated high-performance liquid chromatographic method is described for the determination of the new H+/K+ ATPase inhibitor BY 1023/SK&F 96,022 and its major metabolite occurring in dog serum. The method uses direct sample injection of up to 200 microliters and a pre-column switching technique. In order to optimize the recovery, pre-column conditions were varied systematically with respect to the pH of the pre-column eluent, its buffering capacity and content of acetonitrile. Optimization resulted in near 100% recovery for both compounds, thus allowing the use of external standardization. The linearity range, precision and detection limits were determined and the method shown to be applicable to both serum and plasma. The method was applied to define the pharmacokinetics in dogs and humans.