A planar disposable transdermal iontophoretic delivery system is disclosed which includes amounts of an oxidizable species and a reducible species connected by a common conductor forming a galvanic battery for serving as the sole source of power and control for the system, an amount of a therapeutic agent is provided to be driven through the skin of a patient solely through the use of the galvanic battery. The galvanic battery is provided with a lot-tested coulombic capacity rating to predict dosage.