Feasibility study on the separation and purification of sinomenine hydrochloride from Caulis sinomenii solution based on membrane ultrafiltration technology

The traditional preparation of sinomenine hydrochloride (SH) requires more chloroform and the steps are cumbersome. The use of membrane separation technology can solve the above problems. In this study, Box-Behnken design (BBD) was used to optimize the membrane separation and purification process of SH based on single factor experiments of feed temperatures, diafiltration washing volume, and molecular weight cut-off (MWCO) ranges, the optimized evaluation index is the permeability of SH through the membrane. In addition, to evaluate the effectiveness of membrane separation, the recovery rate of chloroform and the purity of crude SH were compared between traditional separation and purification methods and membrane separation techniques. Finally, the precipitate after extraction was recovered. The optimal process conditions determined are feed temperature of 46 °C, diafiltration washing volume of 75%, and MWCO range of 1 kDa to 150Da. Compared with traditional methods, the implementation of membrane separation can increase the recovery rate of chloroform by 10%. The application of membrane separation technology not only makes the extraction solution clearer, but also reduces the demand for organic solvents during the extraction process. Therefore, this method represents a green and environmentally friendly separation and purification method.