Simultaneous quantification of three alkaloids of Coptidis Rhizoma in rat urine by high-performance liquid chromatography: application to pharmacokinetic study.

A high-performance liquid chromatographic method with ultraviolet detection was established and validated for quantification of three alkaloids (coptisine, palmatine and berberine) in rat urine. Following a single-step liquid-liquid extraction, the analytes were separated on a reversed-phase C(18) column with water-formic acid-triethylamine-methanol as the mobile phase at a flow rate of 1 ml/min. The linear ranges of the calibration curves were 1.6-160 ng/ml for all three alkaloids. The lower limit of quantification was 1.6 ng/ml for all three alkaloids. The within-batch accuracy was 90.4-108.3% for coptisine, 88.6-107.8% for berberine and 88.4-110.1% for palmatine. The between-batch accuracy was 99.3-100.3% for coptisine, 94.3-100.6% for berberine and 93.7-100.0% for palmatine. The within-batch and between-batch precisions were <or=10.1% and <or=11.1%, respectively. This method is suitable to determine the three alkaloids of Coptidis Rhizoma in urine simultaneously and thus to investigate the pharmacokinetics of the alkaloids from Xiexin Decoction in rats.