Ø Iontophoresis is a method of transferring substances across the skin by applying an electrical potential difference. Ø It promotes the transfer of charged ionic drugs and possibly high molecular weight substances such as peptides. Ø Electric current is applied through two electrodes, placed in the patient’s skin. The first, or donor, electrode (cathode) delivers the negatively charged therapeutic agent (e.g., an organic acid), where as the second or receptor, electrode (anode) serves to close the circuit. Ø This setup is named cathodal iontophoresis.For positively charged drugs (e.g., amines or peptides),the cell arrangement is reversed called anodal iontophoresis. The silver (anode) and silver chloride(cathode) electrode system utilized in both types of iontophoresis.