Comparison of the effect of azone and menthol on the percutaneous absorption of indomethacin in vitro

AIM: To compare the permeation enhancing characters of menthol and azone on the model drug of indomethacin and to study the enhancing effect when the two agents were used in combination. METHODS: The transdermal test was conduced on the penetration experiment apparatus of isolated skin. The cumulate penetrated amount, penetrating rate, stable flux and lag time were calculated upon the concentrations. RESULTS: After adding the penetration enhancer, the penetrating rate of indomethacin increased remarkably. It was 6.21 , 4.91 and 6.92 times of that of the controls respectively. When used in combination, the two penetration enhancers increased much more the penetrating rate than being used separately (P 0.01 ). The penetration enhancer could shorten the lag time of absorption of indomethacin evidently. The lag time in the menthol group was shortened more evidently than that in the combined group (P 0.01 ). Azone had little effect on the stable flux of absorption of indomethacin, while menthol decreased it. When the two penetration enhancers were used in combination, distinct enhancing effect was observed. It was 2.78 and 1.38 times of that of separate agents respectively. CONCLUSIONS: Menthol and azone can remarkably enhance the percutaneous absorption of indomethacin in vitro, and the enhancing effect is strongened when they are used in combination.