Simultaneous determination of a new gastrointestinal prokinetic agent (HSR-803) and its metabolites in human serum and urine by high-performance liquid chromatography using automated column-switching.

A method based on high-performance liquid chromatography using column-switching is described for the simultaneous determination of HSR-803 and its metabolites in human serum and urine. The system uses a six-port valve with a Nucleosil CN pre-column for on-line sample clean-up, and direct injection of samples. The limits of quantitation in serum and urine were 5 and 20 ng/ml for HSR-803 and 50 and 200 ng/ml for the metabolites, respectively. The coefficients of variation for the intra- and inter-day accuracies were between 0.8 and 7.1% for each compound. This method was applied to the pharmacokinetic studies in humans after oral administration of HSR-803.