Flow-through methods and apparatus for iontophoresis application of medicaments at a controlled pH

摘要

Methods and apparatus for administering known quantities of medicaments by iontophoresis, while avoiding burns caused by extremes in the pH of the medicament medium during passage of an electric current, are disclosed. It is known that as iontophoresis progresses in conventional iontophoresis systems, the electrolysis of water occurs to produce hydrogen or hydroxyl ions at the interface of the electrode and medicament medium. Since these ions are highly mobile, they are transported directly into the skin of a patient in preference to the larger medicament ions. Thus, extreme changes in pH are experienced which result in burns due to the acidification or alkalinization of the medicament medium and passage of electric current through the skin. In addition, the efficiency of iontophoresis decreases over time. The present invention avoids extremes in pH by removing the hydrogen or hydroxyl ions which are created during iontophoresis and creates conditions for constant delivery over prolonged periods of time. In the present invention, the medicament medium adjacent the patient is periodically or constantly replaced by adding fresh medicament medium which is at the original pH. The present invention also discloses a flow-through electrode which allows new solution to constantly flow into the iontophoresis area.