Skin Permeation Enhancers and their Effects on Narcotic Transdermal Drug Delivery Systems through Response Surface Experimental Design

Drug delivery through skin is often obstructed by low permeability of skin towards most drugs; however، such problem would be solved by application of skin penetration enhancers in the formulations. In the present study، a drug in adhesive patch with buprenorphine as active ingredient was prepared. Drug-in-adhesive transdermal drug delivery systems with different chemical penetration enhancers were designed. For this purpose a response-surface experimental design was used. Response surface methodology based on a three-level، three-variable Box–Behnken design was used to evaluate the interactive effects of dependent variables such as: the rate of skin permeation and adhesion properties including peel strength and tack value. The parameters such as drug release and adhesion were used as independent variables. Levulinic acid، lauryl alcohol and Tween 80 were used as penetration enhancers. In order to prepare samples، buprenorphine with constant concentration was incorporated into acrylic pressure sensitive adhesive with carboxylic functionality and this mixture was added to chemical penetration enhancer with different concentrations. The results show that the cumulative amount of drug release in presence of Tween 80 is 462. 9 ± 0. 006 μg so it is higher than cumulative amount of drug release in presence of levulinic acid (357. 9 ± 0. 005 μg) and lauryl alcohol (269. 5 ± 0. 001 μg). Results of adhesion properties such as peel strength and tack reveal that using levulinic acid and lauryl alcohol will increase peel strength while Tween 80 will decrease it. Besides، the results show that all these permeation enhancers have increased tack values.