Trials and tribulations of skin iontophoresis in therapeutics

Abstract

Iontophoresis is a method of non-invasive transdermal drug delivery based on the transfer of charged molecules using a low-intensity electric current. Both local and systemic administration are possible; however, the skin pharmacokinetics of iontophoretically delivered drugs is complex and difficult to anticipate. The unquestionable theoretical advantages of the technique make it attractive in several potential applications. After a brief review of the factors influencing iontophoresis, we detail the current applications of iontophoresis in therapeutics and the main potential applications under investigation, including systemic and topical drugs and focusing on the treatment of scleroderma-related ulcerations. Finally, we address the issue of safety, which could be a limitation to the routine clinical use of iontophoresis.

Keywords: Iontophoresis; skin; topical drug administration.

Figure 1

Schematic representation of iontophoretic transport. Positively charged drugs (D⁺) migrate under the anode, whereas negatively charges drugs (D^–) migrate under the cathode. The red and blue arrows represent anodal and cathodal electromigration, respectively. The purple arrow represents electro-osmosis

Figure 2

Assessment of the dermal diffusion of a drug administered through cathodal iontophoresis using microdialysis