Iontophoresis: Skin Permeation Enhancement and Applications

Abstract

Transdermal drug delivery (TDD) systems offer a number of potential

advantages over conventional methods such as injectable and oral

delivery as they avoid the first pass metabolism and increase the

patient’s compliance. However, a major limitation of TDDs is that the

skin is highly impermeable to macromolecules and hydrophilic drugs.

The main barrier of drugs across the skin is the skin outermost layer,

the stratum corneum. Application of electricity via the skin is one of

the methods extensively used for enhancing drugs or chemical

substances through the skin. In this article, iontophoresis, a method

for enhancing the skin permeation of hydrophilic drugs, macromolecules,

and charged substances is reviewed. The article also

elaborates on mechanisms that iontophoresis enhances skin

absorption which include electromigration, electroosmosis and

passive permeability. Factors affecting TDD systems using

iontophoresis including electric current, physicochemical properties of

drug and physical properties of the skin are also discussed.

Keywords:

iontophoresis, skin permeation enhancement, factors

affecting skin permeation