NONINVASIVE INVESTIGATION OF HUMAN SKIN AFTER IN-VIVO IONTOPHORESIS

The main objective of our study was to investigate skin function and s tructure in human volunteers after electrical current application in o rder to demonstrate the safety of iontophoresis in vivo. The direct cu rrent was applied for 30 min at a density of 0.1 and 0.2 mA/cm(2). Ion tophoresis increased cutaneous blood flow as measured by laser Doppler flowmetry (LDF). This increase was reversible within 1 h and was more pronounced at higher current density. Measurements of transepidermal water loss (TEWL) and LDF were the same at the cathode and the anode s ites. Except for 5 min at 0.2 mA/cm(2) density, TEWL values were not e nhanced as compared to control values (no iontophoresis). Attenuated t otal reflectance-Fourier transform infrared spectroscopy of the stratu m corneum structure showed a transient increase (30 min) in hydration after electrode application for 30 min. No alteration in lipid structu re could be shown. These results augur the safety of drug delivery by iontophoresis.