The effect of enhancers on percutaneous absorption of osthol across the excised rat's skin

Objective To study the in vitro permeability of osthol across full thickness rat skin treated with enhancers. Methods The modified Valia-Chien diffusion cells was used. Results These enhancers Chenopodium,Menthol and azone are able to increase the osthol percutaneous steady-state fluxes 3.09,3.41 and 4.38 times to that of the control,respectively. To explain the enhancement mechanism of the promoters used,the diffusion and partition coefficients for osthol are calculated. It is indicated that chenopodium,menthol,azone could increase the diffusion coefficients of osthol to 1.10,2.18 and 6.30times respectively to the control,while decrease the SC/medium partition coefficients to 0.309,0.341,0.438 times respectively. Conclusion It is shown that the main enhancement mechanism of three skin penetration enhancer used is to destroy the barrier function of stratum corneum,reducing the resistance of drug transport through the skin and increase the diffusion coefficients of osthol.