A new parameter for characterization of tablet friability based on a systematical study of five excipients

In this paper, a new parameter highly relevant to tablet friability is proposed based on a systematical study of the tablet quality attributes and texture performances of five different direct compression excipients, including microcrystalline cellulose, starch, lactose, mannitol, and dicalcium phosphate anhydrous. The new parameter, named Strain/Stress Max, could indicate the tablet's ability against external force to maintain integrity. It was directly obtained from the diametrical breaking test which is extensively used to assess tablet mechanical strength, and thus no extra work is required. The values varied significantly among the tablets formed by materials with different mechanical properties under the same compression pressure. A design space was developed to achieve <1% tablet friability at various combinations of Strain/Stress Max and tensile strength. Additionally, data from binary mixture tablets validated the availability of the constructed design space. And the upper limit of Strain/Stress Max value was advisable for 1.5 MPa-1 for pharmaceutical tablets. In conclusion, the new parameter and design space are available for fast identification of the tablets with acceptable friability to facilitate the development of tablet formulation using as few active pharmaceutic ingredients as possible.