Objective: According to feature that active ingredients of Bufonis Venenum had poor water solubility

large fluctuation in plasma concentration and toxic side-effects

compound sustained-release dropping pills was prepared with the combination of Bufonis Venenum and Ganoderma. Method: Polyethylene glycol 4000 (PEG4000) and stearic acid were used as matrix to prepare compound Bufonis Venenum sustained-release dropping pills by melting method.Dropping situation was used as the evaluation index to investigate forming factors by single factor experiments.The roundness

weight variation of pills and cumulative release rate in 12 h were used as the evaluation indexes

orthogonal test was adopted to optimize preparation process. Result: Optimum process of compound Bufonis Venenum sustained-release dropping pills was as following:drug-substrate (1:2)

PEG4000-stearic acid (5:1)

melting temperature at 80℃

dropping distance of 8 cm

temperature of pipe orifice in condensate at 50-5℃.The in vitro release of sustained-release dropping pills was 12 h that accorded with Ritger-Peppas model. Conclusion: The preparation process of compound Bufonis Venenum sustained-release dropping pills is stable and feasible.In vitro release of this preparation is similar to non-Fickian diffusion

its release mechanism is the combination of diffusion and matrix dissolution.