Mucoadhesive bilayered buccal platform for antifungal drug delivery into the oral cavity

A drug delivery technology comprising a mucoadhesive bilayered buccally anchored tablet containing natamycin was developed. The concept was to anchor the tablet to the buccal tissue and allow controlled release of the drug through the matrix into the mouth. Carbomer (Carbopol ® 974 P NF) was used to formulate the mucoadhesive layer. Hydroxypropyl methylcellulose (HPMC) (Methocel® K4M) at 10, 15, 20, and 40% w/w was used for the drug-containing layer. Natamycin, an amphoteric macrolide antifungal agent, was incorporated into the formulations. In addition, tablets containing erythrosine as a marker were prepared in order to examine the distribution and retention of the dye in the oral cavity. As expected, the in vitro analysis showed that the concentration of natamycin released decreased with the increasing proportion of HPMC in the formulation. A small volunteer study was conducted using the tablets containing 10% and 20% HPMC to quantitate the patterns of distribution of the drug released into the oral cavity (upper right buccal vestibule, lower right and left buccal vestibules, and sublingual region). The mucoadhesive bilayered buccal tablet formulation provided a unidirectional release of the drug from the tablet into the oral cavity in a prolonged release fashion, maintaining drug concentration above the MIC value (2 μg/mL) for Candida albicans. The amount of the drug in the sublingual region was found to be lowest when compared with other regions, which is due to the higher flow of saliva in this region. Graphical abstract.