Transdermal therapeutic system (TTS), comprising a first compartment and a second compartment, characterized in that: said first compartment, termed "verum compartment", comprises a pressure-sensitive adhesive polymer matrix which contains a pharmaceutical active substance present in the crystalline form, that is in the solid state of aggregation and one side of which serves the purpose of fixing the system on the skin and is covered with an active substance-impermeable, detachable protective layer the second compartment, termed "enhancer compartment", comprises a reservoir which contains one or more skin permeation enhancer(s) present in liquid form, said active substance being partially or completely soluble in the enhance(s) and wherein said two compartments, in the condition of manufacture, are present separate from each other and for the purpose of applying them to the skin can be connected with each other in such a way that side of the first, active substance-containing compartment which is opposite the side covered with the detachable protective layer is connected with the second, enhancer-containing compartment and that a controlled diffusion of the enhancer/enhancers into the active substance-containing compartment is made possible, by means of a control membrane controlling the release of the permeation enhancer(s) from said enhancer-containing compartment, so that in the first compartment an oversaturated system of the active substance, which is present in solid state of aggregation, is formed and wherein the verum compartment and the enhancer compartment, after having been combined with one another, are separated from each other by an "inner backing layer" and the control membrane is arranged between the liquid reservoir and the inner backing layer, which "inner backing layer" is a perforated layer or a layer having high permeability to the permeation enhancer(s).
