An Injection without the Needle: Iontophoresis

Abstract

Penetration of healthy skin by drugs in solution is normally very limited due to the excellent barrier function of the stratum corneum (the most superficial layer of the skin). This barrier can be overcome using iontophoresis: by applying an electrical potential (voltage) across the skin, drug ions become the charge carriers that convey the electrical current through the skin. Iontophoresis is a technique which uses an electric current to deliver a medicine or other chemical through the skin. In popular (lay) terms it is sometimes called "an injection without the needle". Iontophoresis can be defined as a non-invasive method of propelling high concentrations of a charged substance, (normally a medication or bioactive agent), transdermally by repulsive electromotive force using a small electrical charge applied to an iontophoretic chamber containing a similarly charged active agent and its vehicle. This technique of facilitated movement of ions across a membrane under the influence of an externally applied electric potential difference is one of the most promising physical skin penetrations enhancing method.

KEY-WORDS: Iontophoresis, Current, Ions, Transdermal