ABSTRACT
BACKGROUND: The stratum corneum(SC) has a permeability barrier function which regulates percutaneous absorption by the inhibition of transepidermal water loss(TEWL). Acute mechanical or chemical disruption of the SC induces the impairment of the permeability barrier and so increases the TEWL. The calciumtion has been recognized as an important ion in the recovery of the skin barrier. Recently the main delivery pathway of iontophoretic drugs have been suggested by SC interstices. However the morphologic changes in the SC interstices and calcium after iontophoresis have not been reported. OBJECTIVE: The aim of our study is to confirm that iontophoresis may induce changes in the SC interstices and delay the recovery of the barrier after disruption. MATERIALS AND METHODS: After tape stripping the hairless mouse flank skin, the iontophoresis power supply (6V, 0.6mA) was connected to the patch atiached for 2.5 hours to the stripped site. We checked the THWL 0, 2.5, 6, 12, 18, 24 hours after the tape stripping and obtained specimens and performed osmium tetroxide, ruthenium tetroxide postfixation and calcium ion-capture cytochemical stains for electron microscopic study. RESULTS: The recovery rate of the TEWL in iontophoresis was lower than in the control. This was especially so in the anouse which had received anode iontophoresis for 6 hours. It showed statistically lower TEWL than in the control(p<0.05). Anode iontophoresis induced low calcium in stratum granulosum (SG), but cathode iontophoresis induced high calcium in SC. After iontophoresis there were changes in the SC interstices structures. CONCLUSION: Iontophoresis can induce changes in the SC interstices and calcium distribution and so may help the topical drug delivery system.