ABSTRACT
Objective:To study the kinetics of transdermal absorption of volatile oil from Angelica slinesis in fetal skin and investi-gate the mechanism of penetration enhancement in terms of morphology. Methods: Franz diffusion cells were used to investigate the transdermal characteristics in vitro. The content of ligustilide was determined by HPLC, and the cumulative permeation amount per unit area and rate constant of ligustilide were calculated. The effects of volatile oil from Angelica slinesis on skin ultrastructure was observed by a scanning electron microscope and a transmission electron microscope. Results:The kinetics of volatile oil at different concentra-tions was all in accordance with Higuchi equations. The ultrastucture changes of fetal skin under the scanning electron microscope were as follows:the wrinkles on skin surface increased, some areas of stratum corneum peeled off and turnovered like worn-out cotton pad-ding, the follicular orifice was enlarged, and the cuticles of the hair shaft dropped off and became thinner. The changes of fetal skin ul-trastucture under the transmission electron microscope were as follows:stratum corneum cells peeled off, the cell junction in basal lam-ina and stratum spinosum were broken, and the intercellular space was enlarged. Conclusion: The volatile oil from Angelica slinesis has good transdermal permeability. Its enhancement mechanism of transdermal drug absorption is closely related with the effects on skin ultrastructure, which can change the structure of stratum corneum to increase the cell gaps resulting in enhancing drug penetration.