Development and evaluation of mucoadhesive chlorhexidine tablet formulations

Purpose: To formulate mucoadhesive chlorhexidine tablets and evaluate their drug release characteristics and mechanism.
Methods: Chlorhexidine buccal adhesive tablets were prepared by direct compression using a blend of hydroxypropyl methylcellulose (HPMC) and chitosan as the bioadhesive polymers. Their dissolution properties were assessed according to USP 24 (paddle method). In order to determine the mode of drug release from the tablets, the release data were subjected to various release kinetic models. The bioadhesive strength of the tablets was also evaluated.
Results: The results showed that as the proportion of HPMC in the blend increased, drug release rate decreased, with the lowest release rate observed when HPMC alone was used as the bioadhesive polymer (p < 0.001). Both the type and ratio of the polymers used influenced release kinetics. Also, bioadhesion force increased with increasing proportion of HPMC in the tablets, with the highest adhesion force shown when HPMC was the only polymer used, and lowest when chitosan was used alone (p < 0.01).
Conclusion: The chlorhexidine formulations developed showed promise as a bioadhesive delivery system for the drug.

Keywords
Mucoadhesive tablets; Chlorhexidine; HPMC; Chitosan; Release properties; Bioadhesive strength