Transdermal delivery systems are disclosed including a backing layer, a polymer membrane within the backing layer, an adhesive layer for attaching the delivery system to the patients skin or mucosa, and a releasable layer covering the adhesive layer prior to use, the polymer membrane impregnated with sufficient fluid medium to alter the rate of transmission of an active agent through the polymer membrane, with the amount of fluid medium being greater than the amount retained by the fluid membrane upon drying.
