Objective: The aim of this study was to investigate the penetration difference between paeoniflorin gel and paeoniflorin-ethosome gel after dermal application

and then identify the penetration form of paeoniflorin. Method: Improved Franz diffusion cell method were used in the transdermal delivery experiment with rat abdominal skin as in vitro model;and penetration rates

retention amounts on the dermal surface of paeoniflorin in two formulations were investigated.The amount of paeoniflorin in percutaneous receptor fluid and residual drugs were determined by HPLC. Result: The cumulative amount of penetration in paeoniflorin-ethosome gel was 1.76 times bigger than that in paeoniflorin gel and the percutaneous percent was 2.03 times bigger.Both percutaneous results were consistent with zero-level model.Parts of the paeoniflorin-ethosome permeated the skin was in an integrity structure. Conclusion: Because of its deformability and cutaneous integration

ethosome can enhance the permeability of paeoniflorin.