2,6-dimethylbenzenamine was determined as a genotoxic impurity in lidocaine hydrochloride injection, and 2-chloro-N-(2,6- dimethylphenyl) acetamide was determined as potential genotoxic impurity. An LC-MS/MS method was established to research the profiling of genotoxic impurities in active pharmaceutical ingredients (API), homemade preparation and reference preparation on column Agilent ZORBAX Eclipse Plus C18(4.6 mm250 mm，5 μm). The results show that in the homemade preparation the 2,6-dimethylbenzenamine and the 2-chloro-N-(2,6-dimethylphenyl) acetamide may be degraded under oxidation condition and alkaline condition in addition to the introduction from API preparation process. This study provides guidance for genotoxic risk assessment and prescription process optimization of lidocaine hydrochloride.

Hyaluronic acid is widely used in biomaterials, cosmetics, clinical medicine and other fields due to its good biocompatibility, degradability, hydrophilicity, tumor targeting, viscosity and other characteristics. Pharmacodynamic activities of natural small molecular products which derived from traditional Chinese medicine (TCM) are significant, but their low solubility and poor targeting limit the clinical application. Based on supramolecular properties of hyaluronic acid, in this review, numerous studies were reviewed on the improvement of solubility, bioavailability, targeting and suitable dosage forms of small molecular compounds in TCM by domestic and foreign scholars using hyaluronic acid as carrier. It provides new ideas and inspirations for exploring the potential application value of small molecule compounds in TCM and even for the research and development of new drugs.