The prediction of the tensile strength of tablets

Pharmaceutical tablets usually consist of more than a single ingredient, but there appears to be no way of quantitatively predicting the properties of the tablets from a consideration of the properties of the individual components, even for a simple system. We have found for a single material, lactose, which exists in 3 forms, aanhydrous, p-anhydrous and cr-monohydrate, that it is possible to predict the strength of tablets prepared from mixtures of the three forms from measurements of the strength of tablets prepared from the individual components. Tablets were prepared from 0.5 g. of each of the 3 forms of lactose (particle size 0-32 pm) and from 2 and 3 component mixtures of the different forms. The compaction was made at several loads at slow rates with an Instron Physical Testing Instrument modified to take a 1.27 cm flat-faced punch and die system. The tablets produced were subjected to the diametral compression test described by Fell & Newton (1968). A typical example of tensile failure is shown in Fig. 1. To