Effect of penetration enhancers on flurbiprofen permeation through rat skin

To increase the skin permeation rate of flurbiprofen, fatty acids and urea were added in propylene glycol vehicle containing 1% flurbiprofen. The enhancing effects of these compounds on the skin permeation of flurbiprofen were evaluated using Keshary-Chien diffusion cells fitted with excised rat skins. Unsaturated fatty acids increased the skin permeation rate of flurbiprofen 6.5-17.5 fold compared to the control vehicle without enhancer, while saturated fatty acids did not show any significant increase. Although the addition of urea in the vehicle decreased the skin permeation rate of flurbiprofen, the mixture of oleic acid and urea showed a significantly higher permeation rate than oleic acid alone. It was coincident with the results obtained with the plasma concentrations of flurbiprofen determined after the transdermal application of propylene glycol vehicle containing them. AUC and C-max of the vehicle containing the mixture were increased 2.3 and 2.5 fold, respectively, whereas each parameter of the vehicle containing oleic acid only was increased 1.7 fold compared to those of the control vehicle.