Optimization of Slow-Release Tablet Formulations Containing Montmorillonite III. Mechanism of Release

Abstract
The release of sodium sulfathiazole from slow-release tablet dosage forms containing 30% colloidal aluminum silicate and 20% drug, appears to follow first-order kinetics. Analysis of the data however, suggests that several mechanisms including hydration of the clay, diffusion of drug through a hydrated gelatinous barrier and attrition of the gel layer may contribute to the dissolution of sodium sulfathiazole from the tablet matrix. The influence of tablet shape and size on the dissolution properties of drug from the dosage forms was also examined.