Oral mucosal adhesive film containing local anesthetics: in vitro and clinical evaluation

In vitro and in vivo studies were conducted to gauge the effectiveness of a novel oral mucosa adhesive, moderately water-soluble, pliant polymer artificial dentifrice (AD) film containing dibucaine (DC) for relief of pain due to oral erosion. The film was prepared from a hydroxypropyl cellulose-M (HPC-M) ethanol solution containing varying amounts of DC, as well as polyethylene glycol. In the in vitro experiments, the disintegration of HPC-M showed a lag time of about 50 min, a much lower rate than that of drug release, which more or less leveled off after 50 min. Twenty-five percent of the DC was released from the film (0.113 and 0.225 mg/cm2) after the initial 5 min, which then reached about 80% after 50 min, the time at which the polymer began to break up. In the in vivo study, the local anesthetic effect of the film was evaluated in 23 patients (10 males, 13 females) suffering from the adverse effects of chemotherapy. When applied to the wet surface of the mucosa, the AD film absorbed moisture and showed excellent adhesion. Pain relief in patients lasted 2.2 +/- 0.21 and 4.3 +/- 0.25 h at DC doses of 0.113 and 0.225 mg/cm2, respectively. These results suggest that the AD film may cover mucositis sites of oral mucosa long enough to allow DC release and bring relief from pain arising from chemotherapy and/or radiotherapy.