Studies on scutellarin and its degradation kinetics in Dengzhanhuasu Injection / 中草药

ABSTRACT

Objective: To investigate the stability of aqueous solution of scutellarin at different pH values, temperature, ionic strengths, and initial concentration under the condition of dynamic characteristics of the degradation reaction according to ICH guidelines. Methods: The content of scutellarin change with time in different conditions was studied using HPLC method. Based on the chemical reaction kinetics, the parameters of degradation kinetics were calculated under different conditions. The activation energy and half-time (t1/2) were evaluted. Results: The degradation of scutellarin in different conditions followed the first-order kinetics process. The most stable enviroment was in aqueous solutions of pH 7 at 25℃, the half-life period was 203.87 h and the reaction activation energy was 97.9 kJ/mol. But with the temperature increased, the degradation reaction rate greatly accelerated. Under any condition, the stability is higher than the monomer. The initial concentration and ionic strength of Na+ and Cl- had no influence for its degradation. Conclusion: The degradation of scutellarin in different conditions follows the first-order kinetics process and is greatly influenced by the environment of high temperature, strong acid, and weak alkaline. The injection with five kinds of commonly used infusion compatibility is unstable.