The invention relates to transdermal therapeutic system for the transdermal administration of buprenorphine, comprising a buprenorphine-containing self-adhesive layer structure comprisingA) a buprenorphine-impermeable backing layer, andB) a buprenorphine-containing pressure-sensitive adhesive layer on said buprenorphine-impermeable backing layer, the adhesive layer comprisinga) at least one polymer-based pressure-sensitive adhesive,b) an analgesically effective amount of buprenorphine base or a pharmaceutically acceptable salt thereof,c) soluble polyvinylpyrrolidone, andd) a carboxylic acid selected from the group consisting of oleic acid, linoleic acid, linolenic acid, levulinic acid and mixtures thereof, in an amount sufficient so that said analgesically effective amount of buprenorphine is solubilized therein to form a mixture including said polyvinylpyrrolidone, and wherein the carboxylic acid-, buprenorphine- and polyvinylpyrrolidone-containing mixture forms dispersed deposits in the said pressure-sensitive adhesive, andwherein said buprenorphine-containing pressure-sensitive adhesive layer is the skin contact layer.
