Simultaneous determination of baicalin, berberine and rhein in the traditional Chinese patent medicine San-Huang-Pian tablet by HPLC

Aim To establish a reversed phase liquid chromatographic method for simultaneous determination of three main medicinal constituents of baicalin, berberine and rhein in Sanhuang Tablets. Methods The separation was performed on a Kromasil C18 column with TEA-adjusted 0.02 mol?L-1 H3PO4 (pH 6.78)-acetonitrile-methanol (40：9：7) as mobile phase at a flow-rate of 1.0 ml?min-1, with detection at 254 nm. Considering interaction between acidic and alkaline compounds, three standard markers were added respectively and the volume of sample solution was expanded one time in recovery experiments. Results Three regression equations revealed excellent linear relationship between the peak areas and concentrations and the correlation coefficients all surpassed 0.999 8. The average recovery of baicalin is 96.1% (RSD = 2.1%), berberine 98.5% (RSD = 2.4%), rhein 101.5% (RSD = 1.3%). Conclusion The method developed can be used to control the quality of Sanhuang Tablets more comprehensively.