Multilayered polyelectrolyte structures with potential for intracavity drug delivery systems

A design of multilayered polyelectrolyte structures consisting of a substrate of poly-dl-lactide film covered with multilayers of chitosan and casein is reported. An innovative method of corona pretreatment of the substrate was used to ensure the required substrate surface excess charge for the electrostatic attachment of the polyelectrolytes on it. The number of layers was varied from 4 to 16 and the ability of the system to load drugs and to adhere to the buccal mucosa was investigated by means of UV-VIS-NIR spectroscopy, atomic force microscopy, and the small sessile drop technique. At the particular pH and ionic strength used, the optimal number of layers is 8, which results from the loose morphology and complex nature of multilayered structural formation. The drug release is accompanied by polyelectrolyte dissolution.