Electrotransport transdermal system

Claim 1

An electrotransport device for delivering a beneficial agent in the form of a water soluble salt through a body surface, comprising: A donor electrode electrically connected to a donor electrode pad containing the beneficial agent to be delivered, the donor electrode pad being positioned in beneficial agent ion transmitting relationship to said body surface; a counter electrode electrically connected to a counter electrode pad containing a water soluble electrolyte salt, the counter electrode pad being positioned in electrolyte salt ion transmitting relationship to said body surface at a location spaced apart from the donor electrode pad; a source of electrical power electrically connected to the donor and counter electrodes; wherein the donor electrode pad comprises a hydrophobic polymer matrix which is substantially free of any hydrophilic polymer, the hydrophobic polymer matrix containing the water soluble beneficial agent salt blended therein, the beneficial agent salt being present as about 25 to 90 weight % of the total blend of the reservoir and the agent, the blended beneficial agent salt creating a microporous structure in the hydrophobic polymer matrix.