For Surgeons

General

The Renaissance of Iontophoresis.

There has been a resurgence of interest in iontophoresis in the medical profession. Why call it a renaissance of iontophoresis in this day and age? We’ve known about galvanic current for about 200 hundred years and iontophoresis (a word derived from Greek meaning the transport of electrically charged chemicals called ions) through skin was demonstrated almost 100 years ago.

Skin care therapists have used galvanic currents to treat skin for about 70 years –so what can be new?. First activate the skin on negative current, then massage and finally soothe the skin on positive for a refreshed appearance. Right? No! Wrong! Of course these ideas are wrong because they ignore the basic scientific principles. First of all one has to understand that iontophoresis will only occur if the targeted active chemicals have an electrical charge (i.e. they are ions carrying either a positive or negative electrical charge, or will ionise with electricity). When a low intensity galvanic current is applied to a molecule that can dissociate into a positive ion (cation) and a negative ion (anion), then it actually does dissociate more readily in the presence of water and salts. Negative ions move towards the positive pole, and positive ions move towards the negative pole. As a result, ions can be carried to deeper layers of the skin and concentrated there.

If a positive current is applied to the skin together with appropriate gels, then the positive pole will act exactly like a magnet (North Pole repels North Pole and alternately South Pole and vice versa) and repel cations and attract anions. Therefore, if one wants to facilitate the penetration of a cation then one has to apply a positive charge to the skin. However, if one wants to make an anion penetrate deeper into the skin, then one has to apply a negative charge.

To understand iontophoresis better, then one must go back to the very first demonstration of its power. Two rabbits were selected and one poison that has a positive charge was applied to one ear and a poison with a negative charge was applied to the other ear. Only one ear was treated with an electrical current. When the positively ionised poison was treated with a negative current, nothing happened. When positive current was used then the rabbit died! So either positive current was responsible, or the positive poison ions moved through the skin into the blood and killed the rabbit. The second rabbit then proved that it was the ions because when a positive current was used, nothing happened, whereas when a negative current was used, the rabbit died! The only explanation was that the positive and negative ions had been repelled by their similar charges and had gone through the skin. This was a magnificent demonstration but unfortunately not enough people paid attention to it and it was lumped together with things like hypnosis and ignored by the medical profession. In recent years, research workers have looked again at iontophoresis and have tried to define its mysteries. As a result we’ve learned a great deal about iontophoresis and today research workers believe that iontophoresis can very often be as effective as injections into the skin or muscles. Diabetics may one day wear only a simple instrument like a watch and in that way dose themselves with enough insulin to keep themselves healthy. Other powerful medicines can even be taken more than 2cms. Into the body by simple electrical currents. Iontophoresis promises to become a major method for treating people without the use of injections and other invasive techniques. The research workers have realised that we have to know certain properties about ions, not merely that they can ionise. We have learned that the concentration of the ions is important. Not always is the strongest solution the best. We also know now that the properties of the current are important. Certain wave shapes and intermittent application of the current are better than continuous

26 October 2002