Simultaneous quantification of berberine and lysergol by HPLC-UV: evidence that lysergol enhances the oral bioavailability of berberine in rats.

A sensitive and simple HPLC method was developed for the simultaneous quantification of berberine and lysergol in rat plasma. The chromatographic separation was achieved on a C(18) column using isocratic elution with methanol-acetonitrile-0.1% ortho-phosphoric acid (25:20:55, v/v/v), pH adjusted to 6.5 with triethylamine and detected at a UV wavelength of 230 nm. The extraction of the berberine and lysergol from the rat plasma with methylene chloride resulted in their high recoveries (82.62 and 90.17%). HPLC calibration curves for both berberine and lysergol based on the extracts from the rat plasma were linear over a broad concentration range of 50-1000 ng/mL. The limit of quantification was 50 ng/mL. Intra- and inter-day precisions were <15% and accuracy was 87.12-92.55% for berberine and 87.01-92.26% for lysergol. Stability studies showed that berberine and lysergol were stable in rat plasma for short- and long-term period for sample preparation and analysis. The described method was successfully applied to study the pharmacokinetics of berberine as well as lysergol following oral administration in Sprague-Dawley rats. The results of the study inferred that lysergol improved the oral bioavailability of berberine.