Controlled iontophoretic release of glucocorticoids through epithelial cell monolayers

In the present study the iontophoretic transdermal delivery of three different glucocorticoids through a confluent monolayer of MDCK cells, mimicking biological barriers, was studied. For this experiment an in vitro model with platinum electrodes for iontophoresis and MDCK cells was developed. With this model investigations concerning the biocompatibility of the cells depending on different current densities and the iontophoretic permeation of the three glucocorticoids through the cell monolayer were carried out. The permeation behavior of this living biological barrier should be very similar to the non-living barrier, human stratum corneum. Different current densities (12.74-38.22 microA/cm2) and a pulsatile application of continuous current to the cell monolayer were investigated. The pulsatile application of the current resulted in a step-like permeation profile. In all cases the electric current induced an reversible increase of the porosity of the cell monolayer demonstrated by transepithelial electrical resistance measurements and by sodium fluorescein assay.