ABSTRACT
In this paper, five representative Chinese herbal decoction pieces of Scutellariae Radix, Paeoniae Radix Alba, vinegar-processed Corydalis Rhizoma, Polygoni Multiflori Radix Praeparata and Lonicerae Japonicae Flos were selected to prepare the corresponding fine powder of pieces, extract powder, semi-extract powder and physical mixed powder. The physical properties of 20 kinds of powders, such as related parameters of particle size, density, stability and flowability, were evaluated comprehensively. The compression curves of powder porosity and tensile strength changing with pressure were plotted, and the Heckel equation and the Kawakita equation were used to describe the powder compression behavior. The results showed that compared with the fine powder of pieces, the compressibility of the semi-extract powder and the extract powder was significantly improved. Compared with the extract powder, the particle size and relative uniformity of the semi-extract powder were increased, indicating that the uniformity of the powder was improved. Besides, the semi-extract powder could reduce the hygroscopicity of the powder. Particularly, the semi-extract powder of Scutellariae Radix, Paeoniae Radix Alba and vinegar-processed Corydalis Rhizoma could maintain the porous structure of the tablet even under a high tableting pressure, which was beneficial to tablet disintegration. For some traditional Chinese medicines(such as Lonicerae Japonicae Flos), the semi-extract powder could reduce the viscosity, which avoided the sticking in the die compression. The semi-extract powder and the physical mixture powder prepared by the same Chinese herbal decoction pieces had similar physical properties and compression behaviors. Principal component analysis(PCA) was carried out on the 17 physical attributes and 5 compression parameters of the powder. It was found that the first principal component mainly reflected the differences among the material sources, while the second principal component could reflect the differences among fine powder of pieces, extract powder, semi-extract powder and physical mixed powder originating from the same Chinese herbal decoction pieces. In this paper, the mechanism of "unification of drugs and excipients" of Chinese medicine semi-extract powder was explained in terms of physical properties and compression behavior of powders, which provided reference for the formulation design and process development of Chinese medicine tablets.