HPLC-DAD-MS(n) analysis and HPLC quantitation of chemical constituents in Xian-ling-gu-bao capsules

In this study, a systematic method was established for the global quality control of Xian-ling-gu-bao capsules (XLGB), a popular six-herb Traditional Chinese Patent Medicine (TCPM) for the treatment of osteoporosis. Both qualitative and quantitative analyses were conducted. In qualitative analysis part, a fast and sensitive method based on high-performance liquid chromatography coupled with diode-array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-MS(n)) was established for rapid separation and sensitive identification. Samples were separated on a Waters Symmetry C(18) column (250mm×4.6mm, 5μm) by gradient elution using acetonitrile (A) and water-formic acid (B; 0.03%, v/v) as mobile phase at a flow rate of 1.0ml/min. Based on the mass spectra, UV spectra and retention time, 47 compounds were identified or tentatively characterized, including 27 flavonols (all from Epimedii Herba, the major component herb), 4 coumarins, 3 flavonones, 1 chalcone, 3 isoflavones, 1 coumestrol, 3 triterpenoid saponins, 1 iridoid, 3 steroidal saponins, and 1 phenolic acid. Among them, 18 compounds were confirmed by comparing with reference standards. In quantitative analysis part, 10 major compounds in 18 batches of XLGB were simultaneously determined by HPLC/UV detected at 270nm. The method was validated with respect to intra- and inter-day precision, repeatability and stability, with RSD less than 1.0%, 1.5%, 2.9% and 1.8%, respectively. All the 10 analytes showed good linearity in wide linear ranges (r(2)=0.9999), and their average recoveries varied between 97.8% and 104.9%.