How do drug formulators optimize excipients’ processability and performance? Powder rheology enables their work with crucial data insights into excipients’ flow behavior and particle interactions. Powder flow measurements are increasingly important in pre-formulation and formulation stages as pharmaceutical developers continue to push towards quality-by-design approaches.

This paper was written by Jennifer Vail PhD and Sarah Cotts, Rheology Product Specialist. Powder Shear experiments run by Terri Chen, PhD.

Abstract

Powder flow measurements are increasingly important in preformulation and formulation stages as pharmaceutical developers continue to push towards quality-by-design approaches. TA Instruments Powder Rheology Accessory includes two cells for powder measurements: the Flow Cell and the Shear Cell. In this note, the processing behavior of two lactose excipients is studied by measuring shear and flowability of milled and spraydried lactose. Milled lactose was found to have higher cohesion, yield strength, confined and unconfined flow energies when compared to spray-dried lactose. Additionally, milled lactose flow energy exhibited a dependence on impeller tip speed and more variability than spray-dried lactose. The multiple powder rheology measurements presented indicate better processability with spray-dried lactose than with milled lactose.