[Determination of andrographolide and dehydroandrographolide in Andrographis paniculata nees materials and related patent medicines by reversed-phase high performance liquid chromatography].

A simple and accurate method for the determination of andrographolide and dehydroandrographolide in andrographis paniculata Nees materials and patent medicines with high performance liquid chromatography (HPLC) has been developed. The two components were extracted from powdered samples by shaking with methanol. The resultant extracts were separated within 15 min on a BECKMAN C18 column (4.6 mm i. d. x 250 mm, 5 microm) and with a gradient elution of acetonitrile-water at a flow rate of 0.5 mL/min. The detection wavelength was 225 nm and the injection volume was 20 microL. In gradient elution program the volume fraction of acetonitrile in mobile phase was as follows: 0 min - 1 min, 40%; 1 min - 5 min, 40% - 50%; 5 min - 15 min, 50% - 70%. Both andrographolide and dehydroandrographolide have good linearity in the range of 10 mg/L to 100 mg/L with the correlation coefficients of 0.997 6 and 0.998 6 respectively. This method has been successfully applied for the analysis of andrographis paniculata Nees materials and related patent medicines.