Structural identification and comprehensive comparison of saponin-related impurities present in the three different compound glycyrrhizin tablets

Compound Glycyrrhizin Tablet (CGT) is a glycyrrhizin-containing (monoammonium glycyrrhizate, MAG) preparation, which has been widely used in clinical treatment of chronic liver diseases, eczema, atopic dermatitis and other conditions. However, the impurity profile of CGT has not yet been completely elucidated. In this study, eight main saponin-related impurity compounds were initially isolated and identified. Thereafter, based on the characteristic MS/MS fragmentation pathways analysis of the isolated compounds, a novel strategy for characterization and identification of saponin-related impurities was proposed. Then, a total of 41 saponin-related impurities were identified or tentatively characterized in CGTs. Furthermore, principal component analysis (PCA), Wayne diagram and heatmap analysis revealed that the process-related impurity profile in CGTs from three different manufacturers was significantly different. Overall, our findings provided additional technological support for evaluating saponin-related impurities, thereby laying a solid foundation to develop strategies for future product quality improvement.