Objective: To establish the dissolution method of emodin and rheic acid in Sanhuang Tablets and research the dissolution behavior of emodin and rheic acid in Sanhuang Tablets of different pharmaceutical factory. Method: The content of emodin and rheic acid was determined by HPLC. The Grace-C18 (4.5 mm×250 mm

5 μm)column was used

the mobile phase was CH3OH-0.1% H3PO4 (85∶15)

the detection wavelength was 254 nm and flow velocity was 1 mL·min-1. The determination conditions of dissolution were selected

accumulation dissolution curves were calculated

drawn and compared by similarity factor values (f2) and do the model simulation. Result: The determination conditions of dissolution included paddle method with the rotating speed of 100 r·min-1 and 0.1 mol·L-1 hydrochloric acid plus 0.5% sodium dodecyl sulfate as dissolution medium. The result of determination showed that the similarity factor values (f2) of emodin and rheic acid dissolution curves of different pharmaceutical factory of Sanhuang tablets were mostly less than 50. And the dissolution model simulations of this two components are not uniform. Conclusion: There was significant difference in emodin and rheic acid dissolution among Sanhuang tablets of different pharmaceutical factory. The dissolution of the main components should be added to the quality control systems of Chinese patent medicines

and should seek appropriate dissolution mechanism model to describe the dissolution behavior of traditional Chinese medicine.