Quantitative correlation of the effect of process conditions on the capping tendencies of tablet formulations

Capping is a mechanical defect in tablet formulation and manufacture. Understanding what influences tablet capping in terms of process variables and formulation properties and developing specialized techniques to correlate these variables with mechanical failures are practical interests of the pharmaceutical industry. Tablet compression emulator was used to rank order capping tendencies of a diverse sample set. The compression forces of 5-25 kN were used to compress round, beveled edge, and oval shape tablets. Compression speeds of 25, 40, and 80 rpm were chosen as representative ranges for bench-to-manufacturing-scale processing. Tablets were tested by in-house developed nondestructive ultrasonic method. The measurements revealed that elastic modulus vary with different testing orientations that indicated elastic modulus anisotropy in tablets. It was shown that altering process conditions such as tooling, compression force, and compression speed significantly impact the capping tendencies of formulations. A systematic approach has been applied to develop a predictive tool to assess capping tendencies of formulations. The developed tool is fast, material sparing, and has potential to flag the risk of manufacturability issues and provide insight into the performance of formulations during early development.