Determination of five sesquiterpenoids in Xingnaojing injection by quantitative analysis of multiple components with a single marker

A quantitative analysis of multiple components with a single‐marker method was established for the simultaneous determination of five sesqutiterpenoids in Xingnaojing injection. This method was established with Xingnaojing injection determined by high‐performance liquid chromatography coupled with diode array detection. The durability and system suitability of the established method were evaluated, and the reliable relative correction factors were obtained with curdione selected as an internal reference. The contents of the five components in all Xingnaojing injections were determined by external standard method and the contents of curcumenone, curcumenol, curzerenone, and germacrone were also calculated with the obtained relative correction factors. Then, relative error was investigated to estimate the difference of the two methods. As a result, the established new method possesses good adaptability, and there is no significant difference between the two methods, except for the content of curzerenone in eight samples. To put the established method into practice, the limits of quantitation of the established method of the five components were proposed and defined. Thus, the developed methodology can also be utilized to the quality evaluation of Xingnaojing injection, in spite of the difference found in the content of curzerenone between the external standard method and the newly established method.