Rapid resolution liquid chromatography (RRLC) analysis and studies on the stability of Shuang-Huang-Lian preparations

Shuang-Huang-Lian (SHL) is a traditional Chinese formula which comprises of three medicinal herbs: Flos Lonicerae, Radix Scutellariae and Fructus Forsythiae, and is commonly used to treat acute upper respiratory tract infection, acute bronchitis and light pneumonia. A simple, reliable and reproducible rapid resolution liquid chromatography (RRLC) method was developed for the quality control of SHL preparations, which baseline separates the major bioactive compounds within 6min. The method uses a C18-HST column (2.5μm, 100mm×3.0mm) kept at 40°C. The mobile phases consist of 0.1% phosphoric acid aqueous solution and acetonitrile. Flow rate is 1.0ml/min and UV detection is performed at 327nm from 0 to 4min and 229nm from 4 to 7min. This method was further validated according to the ICH guidelines. Eight batches of commercial SHL preparations obtained from different pharmaceutical manufacturers as well as individual herbs were examined and their chromatographic profiles were compared. The stability test revealed that chlorogenic acid is stable only at acidic pH, and hence it is necessary to further evaluate and optimize the preparatory procedures and storage conditions for commercial SHL preparations.