The in vitro and in vivo effects of a fast-dissolving mucoadhesive bi-layered strip as topical anesthetics

To overcome pain on injection, the dentist can apply a topical anesthetic spray. Despite the convenience, it is not easy to apply it locally. So, we developed an oral mucoadhesive bi-layer film containing an anesthetic. We used polyvinylpyrrolidone (PVP)/ hydroxypropyl methylcellulose (HPMC) and HPMC-only layer as the drug-containing layer and ethyl cellulose (EC) as the backing layer. The lidocaine released was tested in vitro together with the adhesion time and cytotoxicity of the film. Mucosa permeability was tested in vivo. Statistical analysis was performed, with p at 0.05 taken to be significant. The lidocaine was released significantly faster in the PVP/HPMC than HPMC-only group and 80% of the drug was released within 1 min (p<0.05) and they attached at least 3 h. The test groups showed no toxicity and the drug effectively permeated the mucosa (p<0.05). We suggest this new mucoadhesive anesthetic may reduce dental phobia.