Studies on effects of enhancers on percutaneous absorption of osthol across excised full thickness rat 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 The enhancers including chenopodium,menthol and Azone were able to increase the osthol percutaneous steady-state fluxes3.09,3.41 and 4.38 times to the control,respectively.To explain the enhancement mechanism of the promoters used,the diffusion and partitioning coefficients for osthol were calculated.It was indicated that chenopodium,menthol and Azone increased the diffusion coefficients of osthol to 1.10,2.18 and 6.30 times respectively to the control,while decreased the SC/medium partition coefficients to 0.309,0.341 and 0.438 times respectively.CONCLUSIONS It was shown that the main enhancement mechanism of three skin penetration enhancers used were to destroy the barrier function of stratum corneum,reduce the resistance of drug transport through the skin and increase the diffusion coefficients of osthol.