Electrochemically Controlled Binding and Release of Dexamethasone from Conducting Polymer Bilayer Films

Conducting polymer bilayer films containing polypyrrole/dexamethasone sodium phosphate as an inner film and poly(N-methylpyrrole)/polystyrenesulfonate or self-doped polyanilinesulfonate as an outer film were prepared by electrochemical and chemical methods. The controlled release of dexamethasone sodium phosphate (DMP) from the inner film was carried out by applying a cathodic potential. The amount of DMP released was investigated by UV–Vis spectrophotometry and electrochemical quartz crystal microbalance. Repeatedly DMP was reincorporated into the inner film, by applying an anodic potential, and then released. The results show that the outer film can act as a barrier to ion and solvent transport between the inner film and the electrolyte which provided a more balanced counter-directional movement of the anions.