A novel texture-probe for the simultaneous and real-time measurement of swelling and erosion rates of matrix tablets

In this note, a novel probe fitted to a texture analyzer was described. This probe has the ability to simultaneously measure, in real-time, dimensional changes in the swollen layer and the glassy core of hydrophilic matrices when exposed to aqueous dissolution media. The utility of this probe was demonstrated on directly compressed tablets containing polymer blends, a water soluble additive, and theophylline as a model drug. Both the erosion and swelling fronts were measured for the same tablet every hour for 12 h. The probe provided accurate thickness data of the swollen region and the glassy core, and was able to demonstrate the swelling and subsequent erosion of the tablet with time. With this method, it is possible to simultaneously measure the swelling rate of the rubbery region and the erosion rate of the glassy core without operator intervention, which provides many advantages over the conventional approaches frequently reported in the literature.