Effects of iontophoresis and electroporation on the stratum corneum - Review of the biophysical studies

This review focuses on the effects induced by iontophoresis and electropora tion on the stratum corneum of the skin. Hence, the aims were: (1) to contr ibute to the understanding of the mechanisms of drug transport by these met hods; (2) to evaluate the safety issues associated with current application . Complementary biophysical methods were used to provide a complete picture of the stratum corneum. Even though the mechanism of drug transport is bel ieved to be different, i.e., electrophoresis for iontophoresis and creation of new aqueous pathways for electroporation, the effects on the stratum co rneum detected minutes after current application are very similar. For both methods, the major findings were: (1) a disorganisation of the lipid bilay ers of the stratum corneum; (2) an increase in skin hydration; (3) a larger decrease in skin resistance induced by electroporation as compared to iont ophoresis. These changes were partly reversible and depended on the amount of electrical charges transferred. The mechanisms of stratum corneum pertur bations are discussed. These perturbations could explain partly the increas e in drug transport. If iontophoresis is considered as a safe method of dru g delivery, the data augurs for the safety of electroporation. (C) 1999 Els evier Science BN. All rights reserved.