Existing issues with traditional Chinese medicine injections: Traditional Chinese medicine injection water generally employs conventional impurity removal processes such as alcohol precipitation and water precipitation. However, extensive research and practical experience have shown that these processes still present several problems: first, the loss of active ingredients; second, suboptimal impurity removal. Tannins, starch, resins, and proteins in traditional Chinese medicine extracts are not easily eliminated by traditional water-alcohol methods, resulting in a high solid yield. This not only causes inconvenience and discomfort for patients during administration but also makes the preparations prone to moisture absorption and deterioration, in addition to poor taste. Application of ultrafiltration membrane separation technology in traditional Chinese medicine injections: Ultrafiltration membranes can intercept particles with a radius ranging from 1 to 20 nm, equivalent to various proteins and high-molecular compounds with molecular weights of 1KDa to 30WDa. They can also intercept colloidal particles of corresponding sizes. Using ultrafiltration membranes with a molecular weight cut-off of 10,000 to 30,000 can essentially ensure the passage of active ingredients while blocking impurities and pyrogens with molecular weights ranging from tens of thousands to millions, achieving the goal of removing impurities while retaining active components. 

Partial applications of ultrafiltration membrane separation in traditional Chinese medicine injections: 

        1. A pharmaceutical company in Xi'an used sulfonated polyethersulfone membranes (SPES) with a molecular weight cut-off of 10,000 for the ultrafiltration-based removal of pyrogens from Astragalus injection, followed by activated carbon adsorption. This increased the product's pyrogen qualification rate from frequent fluctuations to the current 100% compliance.

       2. A domestic research institution used ultrafiltration to prepare several compound traditional Chinese medicine injections, such as Compound Danshen and Yinzhi Hua. The resulting ultrafiltered products exhibited good clarity, with no precipitation observed after three months of storage. Chemical analysis was used to measure the content of tannins, proteins, starch, and other components in the injections. The results showed that the content of these impurities in the ultrafiltered products was below the hygiene standards, indicating excellent impurity removal: