Patent ID: 8197844

Claim:
An active electrode for a medicament patch of the type including a flexible, planar biocompatible substrate with a therapeutic face for disposition against the skin of a patient and a planar medicament matrix having on respective opposite sides thereof a skin contact surface and a securement surface, the securement surface being retained against the therapeutic face of the substrate obscuring a concealed portion thereof with the balance of the therapeutic face defining an exposed portion thereof, the skin contact surface of the medicament matrix effecting electrically conductive engagement with the skin of the patient, when the exposed portion of the therapeutic face of the substrate is retained there against and the medicament matrix is permeated by a medicament, wherein said active electrode is capable of assembly in the medicament patch between the medicament matrix and the concealed portion of the therapeutic face of the substrate, and said active electrode comprises: (a) an electrically conductive backing layer having on respective opposite sides thereof a driving face and a securement surface, said securement surface becoming positioned against the concealed portion of the therapeutic face of the substrate, when said active electrode is assembled in the medicament patch; and (b) a pH-control layer on said driving face of said backing layer covering less than all of said driving face of said backing layer, said pH-control layer and the portion of said driving face free of said pH-control layer together electrically engaging the medicament matrix, said pH-control layer being made of an electrically conductive material capable of moderating changes in the hydrogen-ion concentration in the medicament matrix, when the therapeutic face of the substrate is disposed against the skin of the patient, and an electrical potential is imposed between said backing layer and the skin of the patient remote from the medicament matrix.