ABSTRACT
OBJECTIVE: To remove bacterial endotoxin from glycyrrhizic acid for injection by ultrasonic-assisted ultrafiltration technology. METHODS: On the basis of clarifying the influences of molecular weight cut off, ultrasonic power, glycyrrhizic acid concentration and pH,the ultrafiltration transmittance of glycyrrhizic acid and the rejection of bacterial endotoxin were selected as indexes to optimize the parameters for ultrasonic-assisted ultrafiltration. RESULTS: The impact of glycyrrhizic acid concentration was relatively low. The optimal separation conditions were as following: molecular weight cut off 10×103, ultrasonic power 300 W and pH 7.7. The predicted value of the ultrafiltration rejection of bacterial endotoxin was 93.7%, meanwhile the transmittance of glycyrrhizic acid was 92.2%, which was close to the model-predictive value. CONCLUSION: This mathematical model has good regression with high fitting degree, and can solve the separation contradiction between glycyrrhizic acid and bacterial endotoxin. This study provides scientific data for the purification of pharmaceutics in which saponins are the main components.