In this experiment, the decoction process of famous classical formula Xiebai San was determined by optimizing the particle size of "Cuo san" and investigating the decoction process parameters, such as boiling container, water volume and duration. Xiebai San was taken as an example to explore the study method of the "Cuo san" in the famous classical formulas. The specific chromatogram of Xiebai San and the determination method of glycyrrhizin and glycyrrhizic acid in Xiebai San were established. Different particle sizes of "Cuo san" and decoction parameters were optimized based on the similarity of specific chromatogram, the specific chromatogram's peak area, the content of glycyrrhizin, the content of glycyrrhizic acid and extract yield rate.The particle size of Xiebai San powder was determined to be 2.00-4.75 mm(by four-mesh sieves). The decoction process was determined as follows: put the prescription amount into a ceramic pot, add 420 mL of water, and boil and simmer until the volume is 300 mL.The similarity of specific chromatogram was above 0.9, the specific chromatogram's peak area was larger, the content of glycyrrhizin was 0.12%, the content of glycyrrhizic acid was 0.21%,and the extract yield rate was 15.05%. The finally determined particle size of "Cuo san" can better represent the quality of Xiebai San, and is easy to prepare and suitable for industrial production.This experimental research method can comprehensively investigate the quality of Xiebai San as a whole, the content of active ingredients, and the situation of extract yield.It is a more comprehensive and objective evaluation method, and can provide experimental basis and reference for the study of other "Cuo san" famous classical formulas.
Keywords: Xiebai San; decoction process; famous classical formulas; particle size of "Cuo san"; specific chromatogram.