Processing Parameters for Commonly Used Binders

The intragranular bonds formed during granule drying that contribute to the tablet strength include cohesion of binder film and binder substrate adhesion. Jarosz and Parrott (52) showed that the radial and axial tensile strengths of dicalcium phosphate tablets increased with increasing concentrations of PVP in the formulation (Fig. 4). 

HPMC produced the most friable and smallest granules owing to its lower work of adhesion and cohesion (53). Gelatin produced the strongest granules that needed more work to compress due to their higher resistance to deformation (53). 

Method of Binder Incorporation. PVP can be incorporated in the granulation either by dry or by wet addition methods. The method of binder incorporation affects the granule s properties through its effect on binder dissolution and 

However, granule size enlargement with increasing PVP level reaches a plateau at a critical PVP concentration (25,34). Increasing the PVP level beyond this critical concentration does not lead to further growth of granules but rather widens the size distribution and decreases the friability of the granules (25). 

PVP Concentration. The effect of binder concentration on the properties of granules and tablets prepared by roller compaction is dependent on other processing parameters including feed rate, roll pressure, and speed. Increasing the binder level increases tablet hardness and decreases their friability due to the 

---