Determination of a new oral cephalosporin, S-1090, in human plasma and urine by direct injection high-performance liquid chromatography with ultraviolet detection and column switching.

Direct injection high-performance liquid chromatographic (HPLC) methods with column switching and UV detection were developed for the rapid and accurate determination of S-1090 in human plasma and urine. An internal-surface reversed-phase pre-column and a C18 analytical column were used for the plasma assay. Two pre-columns packed with cyano and phenyl materials and a C18 analytical column were used for the urine assay. The calibration curves for plasma and urine assays were linear in the ranges 0.09-9 microg/ml and 0.5-100 microg/ml of S-1090, respectively. The relative standard deviations for plasma and urine assays were less than 6% with low relative errors. The established HPLC methods were demonstrated to be useful for clinical pharmacokinetic studies after oral administration of S-1090.