Solid-phase extraction and high-performance liquid chromatography for simultaneous determination of important bioactive ginsenosides in pharmaceutical preparations

A robust method based on high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection has been developed for simultaneous determination of six important ginsenosides (Rg1, Re, Rb1, Rc, Rb2, and Rd) in pharmaceutical preparations. For sample preparation, simple and efficient extraction by ultrasonication, combined with solid-phase extraction (SPE) for clean-up, was effective without consuming large amounts of solvent. Chromatographic separation was performed on an ODS column with optimized gradient elution by means of a dual-solvent-pumping system. The validated method results in excellent separation, and quantitative determination is highly precise and accurate. The problem of co-elution of ginsenosides Rg1 and Re is also solved, with good resolution (RS approx. 1.5). Intraday variation was between 0.2 and 4.4% and interday variation was between 0.4 and 6.5% (n=5 for both). The accuracy was satisfactory-in the range 93.9 to 103.4% from replicate evaluation at three different spiking concentrations. Overall limits of detection based on a typical injection volume of 5 mu L were from 1.16 to 1.58 mu g(-1). The validated method enabled complete assessment for quality control of ginseng samples. The technique may be performed with less sample preparation and, consequently, reduced possibility of sample loss.