Thermal Stability of Paeoniflorin in Water Extract and Concentrated Solution of Shujing Fangtong Capsules

Objective:To investigate effects of different factors on the content of paeoniflorin in water extract and concentrated solution of Shujing Fangtong prescription,to optimize process conditions by analyzing thermal degradation kinetics of paeoniflorin.Method:HPLC was employed to determine the content of paeoniflorin with mobile phase of 0.05% potassium dihydrogen phosphate-acetonitrile(85∶ 15) and detection wavelength at 230 nm.Effects of different factors on the content of paeoniflorin in water extract and concentrated solution of Shujing Fangtong capsules.Result:Main factors affecting the content of paeoniflorin were heating temperature and time in preparation process of Shujing Fangtong capsules.Thermal degradation reaction of paeoniflorin in water extract accorded with thermodynamic first-order reaction equation,thermal degradation rate constant(K) increased significantly with increasing of temperature;its thermal degradation reaction accorded with thermodynamic firstorder reaction equation of lg C =-0.002 t + 1.345(r = 0.990 4) in concentrated solution at 80 ℃,K was4.606 × 10-3,validity was 22.88 h,half-life was 150.46 h.Conclusion:High temperature and long time heating should avoid in preparation process of Shujing Fangtong capsules,vacuum concentration method and vacuum drying method should be adopted to reduce degradation rate of paeoniflorin.