General aspects of powder rheology applied to pharmaceutical formulations

Powder flowability is crucial in the pharmaceutical industry, strongly affecting solid dosage processing. Classical experimental techniques offer straightforward results for the rapid screening of formulations during development. However, they fail to describe powder properties under consolidation. Complex techniques, such as shear cell, accurately assess fundamental properties of particulate samples under realistic conditions, enabling prediction of their flow. Ideally, a combination of experimental methods should be used to comprehensively assess powder flowability, ensuring consistent product performance. Moreover, researchers and analytical scientists must have a solid understanding of powder rheology to effectively interpret acquired data. In this review, common techniques, experimental protocols, and typical results observed in a pharmaceutical context are described.