Measurement of Tablet Tensile Strength

The tensile strength of tablets is routinely tested as a measure of tablet quality [2]. It is possible to consider three types of tensile strength - radial, bending, and axial. Here we discuss only the radial tensile strength as it is 

The radial tensile strength is assessed by measuring the diametrical crushing force using what is commonly referred to as a hardness tester . The diametrical crushing force is dissimilar to indention hardness and the use of hardness in the present context is erroneous but nonetheless conventional. Like other mechanical tests, the diametrical crushing force is dependent on the test speed thus, results may vary between testers. 

The speed of the tableting process can be expressed in a number of ways. The term speed may refer to the speed at which the tablet punches advance, the dwell time, the total contact time of the punches with the tablet or the rotational speed of the press. In a conventional tablet press, all of these terms are interrelated. The dwell time is usually defined as the time for the compression wheels to pass over the flat portion of the top of the tablet punch. For the Instron, discussed later in this work, it is the time that the 

The radial tensile strength, t, is calculated from the diametrical crushing force, f, for cylindrical tablets using the relation below [2-4]. 

d is the tablet diameter and h the tablet thickness. It is the radial tensile strength that is commonly determined to assess tablet quality. Procipio et al. [5] have discussed measurement of radial tensile strength. 

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