Iontophoresis

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Iontophoresis is a non-invasive method of propelling high concentrations of a charged substance, normally medication or bioactive-agents, transdermally by repulsive electromotive force using a small electrical charge applied to an iontophoretic chamber containing a similarly charged active agent and its vehicle. To clarify one or two chambers are filled with a solution containing an active ingredient and its solvent, termed the vehicle. The positively charged chamber, termed the anode will repel a positively charged chemical, whilst the negatively charged chamber, termed the cathode, will repel a negatively charged chemical into the skin.

Furthermore, the application of a charge to the skin probably alters the skin’s permeability increasing migration of the active ingredient into the epidermis. There are a number of pathways that the ingredients could take, but research suggests that the majority of drugs permeate the skin via appendageal pores, including hair follicles and sweat glands, although some delivery is via the paracellular channels and minimal quantities are transcellular.

There are a number of factors that influence iontophoretic transport including skin pH, drug concentration and characteristics, ionic competition, molecular size, current, voltage, time applied and skin resistance. Studies suggest that comparable iontophoretic doses delivered at low currents over longer periods are more effective than those delivered by high currents over a short periods.

Iontophoresis is commonly used with anti-inflammatory medications. Common diagnoses treated with Iontophoresis include plantar fasciitis, bursitis and hyperhidrosis. Iontophoresis of Acetylcholine is used in research as a way to test the health of the endothelium by stimulating endothelium dependent generation of nitric oxide and subsequent microvascular vasodilation. Acetylcholine is positively charged and therefore placed in the anode.

This technology is currently being used in such devices as the GlucoWatch which allows for blood glucose detection across skin layers.

Iontophoresis devices for hyperhidrosis

[edit] See also

• Iontocaine
• Electrophoresis
• Vyteris, Inc.