[Research about improving flowability of powder of Chinese herbs extracts by surface modification technology].

In this study, modification technology by surface coating was used to improve the flowability of powder of Chinese herbs extracts. Seven kinds of powder of Chinese herbs extracts were coated with 1% silica nanoparticles using an under-driven Comil. The powder characteristics tester was used to evaluate the flowability of uncoated and coated powders. Surface morphology and particle size distribution of powders were compared by scanning electron microscope (SEM) and optical microscope. The powder hygroscopicity was also investigated. The results showed that, after modification, angle of repose, angle of spatula, compressibility and adhesiveness extremely decreased, and flowability index substantially increased, the powder flowability was significantly improved, especially Gegen and Dahuang extracts powders. Scanning electron microscopy images showed the distribution of silica nanoparticles on the host drug particle surfaces. There were no remarkable changes in the particle size distribution and hygroscopicity of all powders after coating. Therefore, Comilling for surface coating modification technology was an effective method to improve the flowability of Chinese herbs extracts and suggested a possible way forward to enhance the quality of Chinese drugs pharmaceutics in their study and manufacture.