The effect of vehicles and enhancer concentration on the percutaneous absorption of oxybutynin

In order to evaluate the effects of vehicles and penetration enhancers on skin permeation of oxybutynin, the skin peremation rates of oxybutynin from vehicle of different composition were determined using franz diffusion cells fitted with hairless mouse skin. In addition, the effects of fatty acids and fatty alcohols on the penetration of oxybutynin through hairless mouse skins were evaluated. The solvent used were Capryol 90®, Transcutol®, Labrasol ®, Labrafac®, Labrafil® even though permeation rates of oxybutynin from each vehicle were low, the combination Labrafac®/Capryol 90®(70:30) increased it significantly. As the concentration of fatty acids and fatty alcohols varied from 0%, 2%, 5% and 10%, the amount of oxybutynin penetrated were in direct proportion to that of fatty acids but those had no relationship with that fatty alcohol.