OBJECTIVETo establish a simple and rapid method based on diffuse reflectance NIR spectra to in-line monitor the blending process of Zhongsheng pill powder.

METHODZhongsheng pill powder consisted of Zhongsheng spray powder, artificial cowbezoar powder and bile arisaema powder. By means of a revolutionary miniature near-infrared analyzer mounted onto the blender, the powder homogeneity was determined in real time with noninterference. The moving block standard deviation (MBSD) method was used to identify the end point of blending process, providing real-time data and instant feedback about the blending course. Evaluation of blend uniformity was carried out by stratified in-process sampling, and the content of baicalin in samples was determined by high performance liquid chromatography (HPLC).

RESULTThe results calculated through MBSD method were generally coincided with HPLC analysis. Blend homogeneity was assumed to be reached when the standard deviations between spectra approached 0.002, and RSD values of baicalin content in samples from six positions were lower than 5%. Moreover, stratified in-process sampling has significant influence on blending process when the powder loading volume was small.

CONCLUSIONBased on this study, NIR spectroscopy can be possibly extended to be applied in blending process of Zhongsheng pill powder, ensuring a remarkable saving of time and manpower employed and creating a reliable and efficient process measurement technology.