Evaluation of Xanthan Cum as a Hydrophilic Matrix for Controlled-Release Dosage form Preparations

Abstract

Xanthan gum was evaluated as hydrophilic matrix for controlled release preparations. Different parameters were considered: direct and wet granulation, gum concentration, effect of addition of binders, pH, ionic strength, rotation speed and surfactant. Suitable controlled release profile could be obtained. Practically no influence of the parameters studied was noted, with the exception of gum concentration, the rotation speed and presence of ion in the dissolution medium. The release rate profiles were evaluated by different kinetic equations: Zero order, First order, Higuchi equation and RRSBW equation and the data statistically analyzed with F-Ratio. Without binder, in aqueous medium, zero order kinetics were found from the origin of the release rate profile. With binder and dissolution media with electrolytes or buffer solutions, generally zero order kinetics were also found after an initial period of about half an hour. The release kinetics were independent of the method of preparation and compression force.