Objective: To study on in vitro release and transdermal absorption properties of Huoxue Zhitong microemulsion gels.Method: Improved Franz diffusion cell was adopted to investigate in vitro release in semipermeable membrane and transdermal absorption in mouse skin of Huoxue Zhitong microemulsion gels.The contents of paeonol

eugenol and methyl salicylate in receptor fluid were determined by UPLC.Result: In 6 hours

the cumulative release rates of paeonol

eugenol and methyl salicylate were 70.35%

59.40% and 54.64%

the transmission rates of them were 1.138

11.57

73.54 μg·cm-2·h-1

respectively.In 6 hours

the accumulative permeation rates of paeonol

eugenol and methyl salicylate were 40.34%

36.34% and 41.44%

the release rates of them were 0.657

7.127

56.04 μg·cm-2·h-1

respectively.Conclusion: Huoxue Zhitong microemulsion gels has a good in vitro release and transdermal properties

the release laws of all indexes are in accordance with Higuchi equation and the transdermal actions are consistent with zero-order kinetic equation.