Bioadhesive intraoral release systems: design, testing and analysis

The aim of this study was to analyse the adhesion of various polymeric formulations and to measure the in vitro release of a local anaesthetic (febuverine hydrochloride) from a hydrophobic gel containing 34% (wt/wt) adhesive hydrocolloids. The bioadhesive polymer system was prepared from a polyethylene gel containing various amounts of sodium carboxymethylcellulose (NaCMC) as the adhesive, and hydrolysed gelatin as the water sensitive material to ensure rapid swelling. Upon hydration, adhesion studies were performed with a tensile tester equipped with a custom-made cell. The controlled release of the active ingredient was studied with a dissolution cell filled with artificial saliva at 37 degrees C. It was found that the relative adhesive bond strength of the formulations was dependent on the NaCMC content, showing a maximum at about 20 wt %. Febuverine hydrochloride release achieved an optimal release rate for formulations with NaCMC in the range of 12-25 wt %.