[Study on in vitro release and percutaneous absorption for Zhitong cataplasm].

To evaluate in vitro release and transdermal behaviors of Zhitong cataplasm, modified Franz diffusion cell method was applied to investigate in vitro transdermal absorption of Zhitong cataplasm and the content of tetrahydropalmatine was determined by HPLC. In 24 hours, accumulative release rate of tetrahydropalmatine was 81. 9%, transmission rate was 2.26 microg x cm(-2) x h(-1). In 48 hours, accumulative transdermal rate and transmission rate of tetrahydropalmatine were 20.31%, 0.22 pg x cm(-2) x h(-1). So Zhitong cataplasm had a good release and transdermal properties and transdermal actions were consistent with zero-order kinetics process.