This present invention concerns a cover layer that is impermeable to the active substances and/or a removable protective layer of a transdermal therapeutic system, comprising a thermoplastic film which either directly contains the absorbing agents and channel-forming agents or is coated with a polymer support (thermoplast) containing these substances. The polymer support can either be applied over the entire surface of the film or in patterns, directly during production. The thermoplastic film that is used and the polymer support can be made from either the same or different materials.