Effect of menthol on transdermal absorption of paeoniflorin

Objective: To investigate the effects of menthol( different contents) on the transdermal permeation and deposit of paeoniflorin and to determine the appropriate content of menthol. Methods: With a two- chamber diffusion cell as the in vitro experimental apparatus and normal saline as the receiving medium,ultraviolet spectrophotometry was used to investigate the transdermal absorption of paeoniflorin through the in vitro back skin of rats in the presence of 0. 5%,1%,and 2% menthol or azone. Results: The 0. 5% and 1% menthol significantly promoted the transdermal permeation with paeoniflorin,and the paeoniflorin permeation rose as the content of menthol increased. However,when the content of menthol was higher than 2%,the paeoniflorin permeation was reduced. Compared with the control group( in absence of penetration enhancer),the experimental group( in presence of menthol) did not increase the deposit effect of paeoniflorin; azone did not increase the transdermal absorption and deposit of paeoniflorin. Conclusion: Menthol significantly promotes the transdermal absorption of paeoniflorin,but cannot increase its deposit effect. The appropriate content of menthol is 1%.