a pharmaceutical composition for transdermal delivery comprising one or more physiologically active agents ; one or more dermal penetration enhancers ; and a volatile pharmaceutically acceptable carrier comprising a volatile solvent ; and wherein the physiologically active agent and dermal penetration enhancer form an amorphous deposit upon evaporation of the volatile carrier , said amorphous deposit forming a reservoir within the stratum corneum ; and wherein the composition has a release rate profile of physiologically active agent so as to provide a ratio of the maximum concentration to the average concentration for the physiologically active agent over the dosage interval within the range of 1 to 10 .