ABSTRACT
Objective To optimize the extraction method and develop the detection method of ginsenoside Rb1 and astragaloside Ⅳ in Weikang granules. Methods The extraction process of ginsenoside Rb1 and astragaloside Ⅳ in Weikang granules were optimized by single factor investigation, with the contents of ginsenoside Rb1 and astragaloside Ⅳ as optimization indicators. The HPLC-ELSD method was developed for the detection of ginsenoside Rb1 and astragaloside Ⅳ in Weikang granules. Separation was carried out on an XBridge®Shield RP18 column (4.6 mm×250 mm, 5 μm) with a mobile phase consisting of acetonitrile-water（32:68）at the flow rate of 1 ml/min. The column temperature was maintained at 30 ℃. The drift tube temperature was set at 60 ℃, and the carrier gas flow rate was 1.7 SLM. Results The optimized extraction methods of ginsenoside Rb1 and astragaloside Ⅳ in Weikang granules were as the following: methanol reflux extraction for 1.5 h, and n-butanol extraction and ammonia washed for 5 and 2 times, respectively. The HPLC-ELSD method was established to detect the contents of ginsenoside Rb1 and astragaloside Ⅳ. The linear relationship was good (r > 0.9997). The intra-day and inter-day precision was less than 1%. The recovery rates were 95.65% and 100.57%. The stability and repeatability RSD were less than 3%. The contents were 2.8630 mg/g and 0.2576 mg/g. The RSDs were 0.62% and 1.51%, respectively. Conclusion The extraction method of ginsenoside Rb1 and astragaloside Ⅳ in Weikang granules is optimized, and a reliable, accurate and reproducible HPLC-ELSD method for the detection of the contents of ginsenoside Rb1 and astragaloside Ⅳ in Weikang granules is established.