Development and evaluation of extended release bioadhesive sodium fluoride tablets

Localized fluoride delivery to the oral cavity is important in caries prevention. However, no current marketed dosage forms deliver fluoride for an extended period. This work describes the effect of poly (methyl vinyl ether-co-maleic anhydride) mixed calcium/sodium salt (Gantrez MS), sodium carboxymethylcellulose (NaCMC), polyethylene glycol 8000 (PEG8000) and Carbopol 934 (C934) on the in vitro dissolution and ex vivo bioadhesion of sodium fluoride matrix tablets. Dissolution was studied using USP Apparatus 2 and a low volume (3.1 ml), low flow (0.5 ml/min) dissolution apparatus. In both apparatus, the percent drug dissolved at 2, 4 and 8 h was found to be statistically dependent on the fractions of Gantrez MS and NaCMC. The interaction term was significant at 2 and 4 h (probability > (t) of less than 0.05). Ex vivo bioadhesion was studied using excised bovine gingiva and a TA.XT2i Texture Analyzer. Peak bioadhesive force and work of bioadhesion were found to be statistically dependent on the fractions of Gantrez MS and NaCMC with no interaction (probability > (t) of less than 0.01). Results indicate that bioadhesive matrix fluoride tablets of these mixtures can be designed to exhibit both bioadhesive and extended release properties.