International Journal of Pharmaceutics 179 (1999) 1 – 19 Review article Iontophoresis and electroporation: comparisons and contrasts Ajay K. Banga a , Sagarika Bose b , Tapash K. Ghosh c, * a Department of Pharmaceutical Sciences, School of Pharmacy, Mercer Uniersity, Atlanta, GA 30341 -4155, USA b Department of Pharmacal Sciences, School of Pharmacy, Auburn Uniersity, Auburn, AL 36849 -5503, USA c Laipharm Laboratories Inc., Piscataway, NJ, USA Received 24 July 1998; received in revised form 23 October 1998; accepted 23 October 1998 Abstract The techniques of iontophoresis and electroporation can be used to enhance topical and transdermal drug delivery. Iontophoresis applies a small low voltage (typically 10 V or less) continuous constant current (typically 0.5 mA/cm 2 or less) to push a charged drug into skin or other tissue. In contrast, electroporation applies a high voltage (typically, 100 V) pulse for a very short (s-ms) duration to permeabilize the skin. This electric assistance of drug delivery across skin will expand the scope of transdermal delivery to hydrophilic macromolecules such as the drugs of biotechnology. These two techniques differ in several aspects such as the mode of application and pathways of transport but can be used together for effective drug delivery. Iontophoresis is already used clinically in physical therapy clinics and is close to commercialization for development of a systemic delivery patch with miniaturized circuits and similar in overall size to a passive patch. The use of electroporation for drug delivery is relatively new and is being actively researched. © 1999 Elsevier Science B.V. All rights reserved. Keywords: Iontophoresis; Electroporation; Transdermal; Topical; Skin; Drug delivery 1. Introduction Use of electricity to increase penetration of electrically charged molecules through different membranes of our body, a process known as iontophoresis, is known for long time. Biomedical applications of iontophoresis have been around for several decades (Chien and Banga, 1989). In contrast, the use of electroporation for transder- mal or topical delivery was only suggested about 5 years ago (Prausnitz et al., 1993), though elec- troporation as a science has about 25 years of history (Tsong, 1991). A recent text provides de- tailed information on the use of iontophoresis and * Corresponding author. Tel.: +1-732-572-9660. 0378-5173/99/$ - see front matter © 1999 Elsevier Science B.V. All rights reserved. PII:S0378-5173(98)00360-3