Transdermal therapeutic system for the transdermal administration of rotigotine containing an therapeutically effective amount of rotigotine base in a self-adhesive layer structure, comprising A) a backing layer, and B) a rotigotine-containing biphasic layer, the bi phasic layer having a) an outer phase having a composition comprising 75% to 100% of a polymer or a polymer mixture, and b) an inner phase having a composition comprising rotigotine base, wherein the inner phase forms dispersed deposits in the outer phase, and wherein the inner phase comprises i. rotigotine base, and ii. a polymer mixture comprising at least two hydrophilic polymers selected from at least two of the polymer groups: —polyvinylpyrrolidones having a K-Value of at least 80, or from 80 to 200, —polyvinylpyrrolidones having a K-Value of less than 80, or from 10 to 79, —copolymers of vinyl caprolactam, vinylacetate and ethylene glycol, —copolymers of vinylpyrrolidone and vinylacetate, —copolymers of ethylene and vinylacetate, —polyethylene glycols, —polypropylene glycols, —acrylic polymers, —modified celluloses, wherein the polymer mixture in the inner phase is present in an amount sufficient so that said rotigotine base forms a solid solution with the polymer mixture in the inner phase, and C) optionally an additional skin contact layer.
