Transdermal iontophoresis: impact on skin integrity as evaluated by various methods

Transdermal iontophoresis, a noninvasive technique that facilitates drug transport through the skin by the use of an external electrical field, has expanded the scope of drugs that can be delivered transdermally and enables programmable drug delivery. In general, transdermal iontophoresis is considered to be a safe procedure, associated with moderate erythema and tingling sensations. However, ensuring that the skin barrier maintains its integrity during iontophoresis is an essential factor to increase its clinical applicability. This review focuses on the effect of transdermal iontophoresis on the integrity of skin, as evaluated by impedance spectroscopy, microscopy, differential scanning calorimetry, infrared spectroscopy, X-ray diffraction, transepidermal water loss, laser doppler velocimetry, visual scoring, chromameter readings, and patient evaluation studies.