Viscometric study of pectin–mucin interaction and its mucoadhesive bond strength

The rheological characteristics of aqueous dispersion of four types of pectin and their mixtures with mucin were investigated using a simple viscometric method with a Brookfield viscometer, and were compared to the known mucoadhesive chitosans and Carbomer934P. The viscometric method introduced the parameter, ηenhance or viscosity enhancement, which is an empirical determinant of the absolute force of bioadhesion. The higher the molecular weight, the greater the ηenhance indicating the rheological synergism. The force of bioadhesion was also found to be dependent on molecular weight of pectin, its initial viscosity and environmental pH. These results are in agreement with an already reported in-vitro test on gastrointestinal mucosa. This corroborates the use of pectin as a mucoadhesive polymer for gastrointestinal mucoadhesive drug delivery system.