Measurement of hardness and strength of tablets and their relation to compaction performance of powders.

Materials with different deformation properties were compressed into tablets at a range of pressures. The compacts were characterized in terms of indentation hardness which quantifies resistance to deformation and tensile strength quantifying resistance to fracture. A unifying description of these two competing mechanical responses is made using the evaluated single compaction parameters obtained with the equation proposed by Leuenberger. The compaction performance parameter and the bonding index make it possible to characterize the deformation and bonding behaviour of a substance under pressure. Furthermore, useful information is obtained for predicting when capping problems occur. It is evident that more than one index or parameter is necessary to describe the variety and complexity of the tableting properties.