Determination of a new antiulcer agent, eupatilin, in rat plasma, bile, urine, and liver homogenate by high-performance liquid chromatography.

A high-performance liquid chromatographic method was developed for the determination of a new antiulcer agent, eupatilin, in rat plasma, urine, bile, and liver homogenate. The method involved deproteinization of biological sample with the same volume of acetonitrile. A 100 microl aliquot of the supernatant was injected onto a C18 reversed-phase column. The mobile phase employed was ammonium acetate buffer (1% ammonium acetate and 0.5% acetic acid) - acetonitrile (58:42, v/v) and the flow rate was 1.0 ml/min. The column effluent was monitored by a ultraviolet detector set at 350 nm. The retention time for eupatilin was approximately 6.5 min. The detection limits for eupatilin in rat plasma, urine, bile, and liver homogenate were 50, 50, 100, and 100 ng/ml, respectively. The coefficients of variation of the assay were generally low (below 7.46%) for rat plasma, urine, bile, and liver homogenate. No interferences from endogenous substances were observed.