Objective: To investigate effects of different penetration enhancers on transdermal permeation of tetrahydropalmatine from Baijiezi San patches and provide a reference for development of this preparation. Method: Modified Franz diffusion cell was adopted

with excised male rabbits skin as model

HPLC was adopted to determine the content of tetrahydropalmatine with mobile phase of methanol-0.1% phosphoric acid(adjusting pH to 6.0 with triethylamine) (60:40) and detection wavelength at 280 nm.Accumulative permeation quantity of tetrahydropalmatine was fitted

in order to investigate effects of different penetration enhancers on transdermal permeation of Baijiezi San patches. Result: Accumulative permeation quantity of Baijiezi San patches with 2% azone as penetration enhancers was highest.When combination of penetration enhancers

transdermal permeation of 2% azone combined with 5% propanediol was better

but its effects was weaker than 2% azone alone. Conclusion: Azone can significantly improve transdermal absorption of Baijiezi San patches.