Thin-Film Composites (TFC) comprise a bi-layer film having both a pH-sensitive mucoadhesive layer to promote strong adherence to the skin and mucosal surfaces, as well as a specially bonded wax layer intended to extend the adherence of the film to tissues for a prolonged period of time. TFC is non-irritating to buccal tissue and can be utilized to deliver small molecules, peptides, proteins, and nucleic acids either locally to act at the site of administration or for the absorption of said molecules of interest across biological membranes into the systemic circulation. Stable loading and release of small molecules, peptides, proteins, and plasmid DNA have been demonstrated.
In rabbits, TFC were utilized to increase the relative bioavailability of testosterone to 50% when administered by the buccal route without a chemical penetration enhancer. In rabbits, TFC were developed to deliver biologically active salmon calcitonin via the buccal route, resulting in a decrease in plasma calcium levels. Mucosal (genetic) vaccine studies using TFC in vivo in rabbits have shown enhanced humoral and proliferative immune responses over conventional subcutaneous injection of adjuvanted protein antigen.