Transdermal delivery system with two superimposed adhesive layers having different affinities to the active substance comprised

摘要

A device for the transdermal delivery of a pharmacologically active substance has first and second superimposed mutually contacting adhesive layers ( 2, 3 ). The first layer ( 3 ) is in use brought into contact with the skin. The active substance is dissolved in both layers, the affinity of the first layer for the active substance being between about 1.15 and about 10 times lower than that of the second layer. The percent saturation of the active substance in both the layers is the same and is less than 100%. The first layer has a greater thickness than the second layer. The device is simple and can provide stable delivery over a long period.