Comparative study for pharmaceutical quality among bland-name drug and generic drugs of compound glycyrrhizin injections in China

The physicochemical properties (pH and osmolarity), ingredients, and impurities containing in compound glycyrrhizin injections (eight items) marketed in China were compared with those in bland-name drug (Stronger Neo-Minophagen C injection). Glycyrrhizin (GZ), glycine (Gly), and l-cysteine (CysH) as the ingredients, moreover, glycyrrhetinic acid (GA), 3-monoglucuronyl-glycyrrhetinic acid (MGGA), and l-cystine (CysS) as the impurity were determined by HPLC. The pH and osmolarity were different every each pharmaceutical product, but the variation between batch was very small. On the other hand, although the contents of GZ, Gly, and CysH in bland-name drug were approximately 100% of the label claim, the contents of GZ in generic drugs were the range of 91.8-100.9%, indicating the GZ contents in four products were clearly less than value indicated in label (<97%). The remarkable difference was not accepted by impurities content such as GA and MGGA. The contents of CysH in generic drugs were the range of 79.9-100.4%, and CysS was determined in all generic drugs, suggesting that CysH may decompose to be CysS depending on the pH of injections in generic drug only. Because the variation of the ingredient content was big and products with a little quantity for the ingredients were recognized, establishment of the preparation that can maintain the prescribed ingredient content and the severity of the assay will be required.