Impact testing as a new approach to determine mechanical strength of pharmaceutical tablets

Abstract

One of the most common standardised testing of tablet strength in the pharmaceutical industry is the tablet breaking force, which records data related to diametrical compression. This method does not account for a rapid transfer of energy such as free-falling tablets hitting a solid surface, which occurs throughout manufacture, packaging and shipping. Accordingly, the test shows poor correlation with tablet defect rate. Impact fracture force was identified as a test to measure the force absorbed by the material before fracturing when applying impact energy (dynamic stress). The testing methodology for impact fracture force was modified and developed to characterise pharmaceutical tablets. A wide range of tablet formulations with different compositions, sizes, shapes and strengths were evaluated. The results showed that the measured impact fracture force had superior correlation with tablet defect rate in comparison to the standard pharmaceutical tests for breaking and friability with good repeatability. This is the first instrumented impact fracture force tester for pharmaceutical tablets that enables quality by design robust products to withstand and survive mechanical stresses during the manufacturing process. This method has the potential to save extra resource and cost required to solve issues around tablet defects including manufacturing deviations, tablet waste, extra appearance testing, visual inspection and tablet sorting.