The impact fracture wear test: A novel method of tablet evaluation

Abstract

Tablet strength is usually determined by the diametral compression test or by the indentation hardness test. However, the limited data available from such tests make the development of a new test desirable. For this purpose, this report describes the development of a modified friability test, named the ‘impact fracture wear test’. It provides data which are not solely dependent upon the greatest flaw in the tablet and it stresses the tablet in a manner similar to subsequent processing. The relationship between tablet half-life ( t 50), a strength parameter, and relative density, and the effects of dwell time and particle size, were found to be similar to those described in the literature. The wear of castings of Plaster of Paris fits a first-order kinetic model well. The wear of compacts of sodium chloride deviates increasingly from first-order kinetics with increasing grain size and porosity. These deviations may be correlated with the non-homogeneity of tablet strength, the effects of tablet geometry, and of changes in process variables such as humidity, lubrication, preconsolidation, and storage time. Examination of the tablet and its wear fragments during the test provides information about the deformation and fracture characteristics of the material.