OBJECTIVETo develop a reliable method to assess the stability of xinyue capsules containing Panax quinquefolius saponins according to European quality standards.

METHODSAn efficient high-performance liquid chromatography ultraviolet (HPLC-UV) method was established to analyse six main ginsenosides (Rb1, Rb2, Rc, Rd, Re and Rg1) in six different batches (120 capsules/batch) from the same lot of xinyue capsules and in one batch measured six times within one day. The six ginsenosides were separated on a Hypersil BDS-C18 column (3 μm, 100 mm×3 mm) at a flow rate of 0.5 mL/min. Gradient elution was performed using a mobile phase gradient of acetonitrile-water modified with 0.01% formic acid. The HPLC chromatograms were analyzed with "LC data comparison" using Lab Solutions software.

RESULTSThe HPLC peaks were identified by comparing their retention times (Rg1: 23.44 min, Re: 23.77 min, Rb1: 35.24 min, Rc: 36.18 min, Rb2: 38.55 min and Rd: 40.88 min) with those of the standards under the same chromatographic conditions, which showed similar results among the samples of six different batches and among the samples from one batch detected six times within one day.

CONCLUSIONSXinyue capsules have good drug intra-day consistency at room temperature and exhibit a consistent quality between different batches. This study established a reliable method to assess the stability of xinyue capsules, which is suitable for further qualitative analysis and may assist in promoting the safe and effective use of Chinese herbal medicine.