Research progress on percolation extraction process of traditional Chinese medicines / 中国中药杂志

Percolation extraction is a conventional extraction method used in the processing of traditional Chinese medicines. After medicinal material powder is placed in a percolation tank, the extraction solvent is continuously added, and percolation extract is collected simultaneously. The percolation equipment is simple. The percolation operation is easy. It is applicable to a wide range of medicinal materials. Components that are unstable under thermal conditions can be effectively extracted. However, there are also disadvantages, such as high solvent consumption, long extraction time, and high energy consumption in subsequent concentration processes. This article mainly reviews the research progress on the common equipment types, affecting factors, parameter optimization methods, and process monitoring. According to analysis on literatures, solvent composition, impregnation time, percolation speed, and solvent consumption are considered as the important factors of percolation processes. At present, near-infrared spectroscopy is widely used in the monitoring of percolation process, and partial least square is a commonly used quantitative modeling method. According to the concept of "Quality by Design", in-depth investigation of the percolation process mechanism and development of process control methods are future development trends. Therefore, process modeling, process optimization and process monitoring shall be improved. The mechanism models and the empirical models of column chromatography can be used as references to construct the percolation process models. The effect of the quality changes of medicinal materials shall be taken into account when optimizing the percolation process parameters. More simple and easy methods shall be developed to monitor the percolation process status and key properties of percolation extracts.

An on-line near-infrared spectroscopy approach for content determination in the percolation process of compound Kushen injection / 中国药学杂志

OBJECTIVE: To develop an on-line analysis method based on near infrared spectroscopy (NIRS) for monitoring the percolation process of compound Kushen injection traditional Chinese medicines. METHODS: Samples and correlative spectra were collected with online equipment in percolation process. The contents of total alkaloids and total solids measured with standard methods were used as reference values. Multivariate calibration models based on partial least squares (PLS) algorithm were developed to correlate the spectra and the reference values. RESULTS: The correlation coefficients of the calibration models for total alkaloids and total solids were 0.9979 and 0.9960 with root mean square errors (RMSECs) of 0.0721 g · L-1 and 0.0811%, respectively. External validation samples collected on-line were used to evaluate the quantitative models. The correlation coefficients between the predicted value and the reference value were 0.9915 and 0.9990 with root mean square errors of prediction (RMSEPs) of 0.1950 g· L-1 and 0.0681%, respectively. CONCLUSION: The presented method is rapid, accurate and reliable, which can be used for monitoring the percolation process of compound Kushen injection.