Iontophoresis Vineela.U 08B21A0538 CSE

Introduction Introducing of ions into the body using direct electrical current. Use of dielectric current to facilitate delivery of ions into the skin for therapeutic purpose. Transport ions across a membrance or into a tissue.

History Concept first developed & researched over a century ago. Therapeutic use for more than 50 years. Popularity & usage was declining until Joseph Kahn PhD, had 9 publications from 1973 to 1983. All case studies & clinical commentaries.

IONs Positively charged ions are driven into tissues from positive pole Negatively charged ions are driven into tissues from negative pole Knowing correct ion polarity is essential Positive Electrode (anode) delivers + ions Negative Electrode (cathode) delivers - ions

Movements of IONs in Solution Anode = Positively charged electrode Lower concentration of electrons Repels positively charged ions Attracts negatively charged ions Accumulation of positively charged ions in a small area creates an alkaline reaction Cathode = Negatively charged electrode Highest concentration of electrons Repels negatively charged ions Attracts positively charged ions Accumulation of negatively charged ions in a small area creates an acidic reaction

Movement of IONs in Tissue Force which acts to move ions through the tissues is determined by Strength of the electrical field . Electrical impedance of tissues to current flow. Sweat ducts are primary paths by which ions move through the skin.

The quantity of ions transferred into the tissues through iontophoresis is directly proportional to Current density. Duration of the current flow. Concentration of ions in solution. Once the ions pass through skin they recombine with existing ions and free radicals in the blood thus forming the necessary new compounds for favorable therapeutic interactions .

Ion Transfer Rate at which an ion may be delivered is determined by a number of factors The concentration of the ion The pH of the solution Molecular size Current density Duration of the treatment

Ionotophoresis Generator Intensity control 1 to 5 mA Constant voltage output that adjusts to normal variations in tissue impedance thus reducing the likelihood of burns Automatic shutdown if skin impedance reduces to preset limit

Adjustable Timer Up to 25 min

Lead wires Active electrode Inactive electrode

Procedure To ensure maximum contact of electrodes skin should be cleaned prior to attachment of the electrodes. Do not excessively rub skin during cleaning since damaged skin has lowered resistance to current and a burn might occur more easily .

Preparation of Electrode Attach self-adhering active electrode to skin. Inject ionized solution into the chamber. Attach self-adhering inactive electrode to the skin and attach lead wires from generator to each.

Current Intensity Low amperage currents appear to be more effective. Higher intensity currents tend to reduce effective penetration into the tissues. Recommended current amplitudes used for iontophoresis range between 3-5 mA .

Increase intensity slowly until patient reports tingling or prickly sensation. When terminating treatment intensity should be slowly decreased to zero before electrodes are disconnected. Current amplitude usually set so that current density falls between 0.1-0.5 mA/cm2 of the active electrode surface.

Treatment Duration 10-20 minutes. Average 15 min. Check skin every 3-5 minutes for signs of skin irritation. Patient should be comfortable. Decrease intensity during treatment to accommodate decrease in skin impedance to avoid pain or burning.

Contraindications Skin sensitivity. Sensitivity to agent. Gastritis/ulcer- cortisone. Asthma- mecholyl. Sensitivity to metal. Sensitivity to seafood-iodine. Recent scars in treatment area. Metal implants close to skin. Acute injury where there is still bleeding.

Advantages It is a painless,strile,noninvasive technique. Less drug into systemic circulation. Decreased side effects. Potentially greater concentration of drug in the target area. Supervised. Safer than administering a drug through injection.

Disadvantages Risk of skin irritation or burn. Depth of penetration known to vary. Most common problem is a chemical burn which occurs as a result of direct current itself and not because of the ion being used. Thermal burns may occur due to high resistance to current flow created by poor contact of the electrodes with the skin.

Conclusion Iontophoresis is a method of choice in administration of certain local anesthetics and has had its greatest success in therapy. Knowledge of the mechanism and instrumentation increased exponentially in the last decade. New applications are to be expected, particularly in administration of peptide and protein drugs.