A novel process for developing a quantitative chromatographic fingerprint analysis method based on analytical quality by design: A case study of Xiaochaihu capsules

In this study, an improved Analytical Quality by Design (AQbD) process was proposed to establish quantitative fingerprints of Chinese medicines. A quantitative fingerprint method for the strong polar components in Xiaochaihu capsules was developed as an example. Different method evaluation indicators were used to characterize this method, and these indicators were measured at different stages of quantitative fingerprint development. Through this method, the difficulty in determining common peaks in the early stage of quantitative fingerprint development is eliminated. The method parameters that needed to be optimized were the mobile phase gradient conditions, column temperature and flow rate through the Ishikawa diagram. Single-factor experiments were used to determine some parameters. Definitive screening design (DSD) experiments were used to optimize critical method parameters (CMPs). The common peaks were determined, and indices were optimized. The critical method attributes (CMAs) were the resolution of guanosine, the percentage of common peak to the total peak area, retention time of the last peak and the common peak number. A stepwise regression method was used to build quantitative models for critical method attributes and critical method parameters. The method operable design region (MODR) was calculated by the experimental error simulation method and successfully verified. After the analysis conditions were optimized, four components, uridine, adenine, 5-hydroxymethylfurfural, and guanosine, were quantitatively determined. There were 7 common peaks in the fingerprints. The common peak area accounted for 90.64%. Both fingerprint and quantitative detection analysis methods were methodologically validated. The new AQbD process proposed in this study can be potentially applied to develop other Chinese medicines fingerprint methods.