ABSTRACT
Objective: To study the powder characteristics and dissolution behavior of the composition in decoction for boiling powders of Chinese materia medica, and to provide scientific evidence for particle size control and its application. Methods: Four kinds of herbal pieces such as Scutellariae Radix, Coptidis Rhizoma, Puerariae Radix, and Glycyrrhizae Preparata Radix were prepared in powders. Powder characteristics including particles distribution and mobility, and dispersion properties of particles in the water decoction were investigated. Additionally, dissolution behaviors of the composition in decoction made from powders and pieces were compared. Results: Well-distributed particles and high mobility were observed in Scutellariae Radix, Coptidis Rhizoma, and Glycyrrhizae Radix Preparata powders, rather than in Puerariae Radix powder. The suspended particles in the decoction in both powders and pieces were submicron. However, optical and electrical properties showed that the suspended particles in the decoction made from powders were more, bigger, and easier to settle as heterogeneous liquid was. Dissolution velocity and amount of the active ingredients in the decoction made from powders were significantly higher than those of pieces. Conclusion: As a new type of herbal decoction which could increase the dissolution of active ingredients, it could shorten decocting duration and improve the availability of herbs. The boiling powders are worth being studied and promoted.