THE EFFECT OF CURRENT ON SKIN BARRIER FUNCTION IN-VIVO - RECOVERY KINETICS POST-IONTOPHORESIS

Purpose. The objective of this study was to determine the extent to wh ich current passage perturbed the skin's intrinsic permeability, and t o quantify how quickly and to what extent the barrier properties recov ered from the effects of iontophoresis. Methods. Laser scanning confoc al microscopy (LSCM) and impedance spectroscopy (IS) were employed, re spectively to visualize and quantify the recovery kinetics. Results. L SCM images were obtained following passive calcein diffusion through p re-iontophoresed HMS skin in vivo that had been allowed to recover for progressively longer periods of time. IS was used to quantify the rat e and extent of skin permeability recovery following current pretreatm ent. Impedance spectra were recorded 0, 3, 5, 7, 9 and 18 hrs after cu rrent termination. Conclusions. Enhanced calcein permeability as asses sed by confocal microscopy persisted for up to 24 hrs following curren t passage. Consistent with these LSCM findings, IS indicated that the time required for the impedance of hairless mouse skin to return to pr e-iontophoresis levels (following 2-hr current passage at 0.5 mA/cm(2) ) was at least 18 hrs.