Passive and iontophoretic controlled delivery of salmon calcitonin through artificial membranes

The development of a transdermal delivery system for drug molecules of high molecular weight (peptides or proteins) is nowadays a great scientific and commercial challenge. For these molecules, the passive transport through the skin is generally very low and should be enhanced by the application of the electrical current (a method called iontophoresis). A very important component of a transdermal iontophoretic system is the artificial membrane, which acts as the interface between the drug reservoir and the skin. The optimum membrane should (i) provide an effective drug delivery; (ii) have low electrical resistance and (ii) have low drug adsorption. In this work, the selection of membrane(s) for a transdermal iontophoretic salmon calcitonin (sCT, MW approximately 3500) system is performed. The passive and iontophoretic transport of sCT through porous artificial membranes, the sCT adsorption to them and the electrical resistance of all porous membranes in iontophoretic experiments is studied. The sCT transport through the membranes is compared with that through human skin, and based on the above three criteria the optimum membranes are selected for the sCT transdermal system.