Integrating chemical similarity and bioequivalence: A pilot study on quality consistency evaluation of dispensing granule and traditional decoction of Scutellariae Radix by a totality-of-the-evidence approach.

There is an increasing focus on the quality consistency evaluation of dispensing granule in traditional Chinese medicines (TCMs). According to the guideline from Chinese Pharmacopoeia Commission, the substantial equivalence of dispensing granule and traditional decoction should be determined, and the chromatographic fingerprint has been recommended as a comprehensive qualitative approach to assess the quality consistency between dispensing granule and traditional decoction. However, a high-degree chemical similarity does not equal a bioequivalence. Attempting to realize the quality evaluation by integrating chemical consistency and bioequivalence, we herein proposed a totality-of-the-evidence approach based on clustering analysis and equivalence evaluation taking the dispensing granule and traditional decoction of Scutellariae Radix (SR) as a typical case. Chemical fingerprints were developed by high performance liquid chromatography coupled with photodiode array detector and quadrupole time-of-flight mass spectrometry (HPLC-PDA/QTOF-MS). Subsequently, a feature selection strategy, integrated linear and nonlinear correlation analysis, was carried out to assess the correlation between chemical profiles and biological activities. Finally, quality consistency between the dispensing granule and the traditional decoction was determined by bioactive marker-guided hierarchical clustering analysis (HCA), k-means clustering method and bioequivalence evaluation. The available evidence suggested that not all the dispensing granule of SR were sufficiently similar to the traditional decoction. This study provides an applicable methodology for quality consistency evaluation of dispensing granule and traditional decoction in TCMs.