Objective: To investigate influence of forced circulation dynamic technology upon extraction effect of Liuwei Dihuang pills. Method: With extraction ratio of loganin and dry extract ratio as indicators

under premise of extraction times without changing from the existing standard of the product

orthogonal design was used to investigate effects of the amount of adding water and extraction time on dynamic extraction technology of Liuwei Dihuang pills

and compared with traditional extraction methods.HPLC was established to determine the content of loganin with mobile phase of tetrahydrofuran-methanol-acetonitrile-0.05% phosphoric acid solution(1:4:8:87) and detection wavelength of 236 nm. Result: The amount of adding water had significant difference influence on extraction amount of loganin and dry extract ratio

but extraction time had no significant difference.Optimum dynamic extraction technology was as following:extracted twice with three times the amount of water

one hour per time;Average extraction amount of loganin was 1.068 mg·g-1

average rate of dry extract was 25.75%. Conclusion: This optimized technology was stable and feasible with characteristics of energy saving

time-saving

high extraction rate and so on

it was suitable for industrial production of Liuwei Dihuang pills.