Design and evaluation of bilayered buccal film preparations for local administration of lidocaine hydrochloride

Bilayered oromucosal film preparations (buccal films) offer a promising way to enable drug administration via the oral cavity. Adding a non-soluble or slowly eroding/dissolving backing layer to a mucoadhesive drug-loaded layer enables unidirectional drug delivery.The aim of this study was to investigate different approaches to the manufacture of bilayered films and to examine their properties by applying different characterization methods including an optimized experimental setup for the study of drug release from bilayered films. A solvent suitability study was performed screening over 15 polymers with respect to their feasibility for viscous film formation for film preparation by solvent casting method. Two methods (double-casting and pasting) were found as suitable methods for bilayered film manufacturing. Results from drug release experiments indicated that slowly eroding hypromellose backing layer films revealed the best shielding of the drug-loaded layer to enable unidirectional drug release. In summary, manufacturing of bilayered films using the described methods was feasible. Furthermore, the use of an optimized experimental setup for drug dissolution studies enabled monitoring of drug release without delays in sampling.