Powder dispersibility characterization using gas-pressurized dispersive technology: Interplay effects of powder mass and powder dispersibility tester contact surfaces

Abstract

This study re-invented gas-pressurized powder dispersibility tester (9 g) to accommodate a lower test sample mass (2 g). Powder contact surfaces with smooth, diffuse and dense asperities were designed as rough surface was foreseen to result in cohesive powder exhibiting poorer dispersibility thereby allowing differentiation from free flowing powder. The powder dispersibility characteristics of seven lactose grades were examined against Hausner ratio (HR) and Carr’s index (CI) as standard reference values. Using smooth-surface variant, the powder dispersive distance and in particularly surface area were correlatable to HR/CI to a greater extent with 2 g than 9 g load. With dense asperities surface, insignificant correlations were found between surface area of powder dispersion with HR/CI as a result of powder shearing against the asperities into less aggregative particles which were not reflective of those in HR/CI tests. Smooth powder contact surface is preferred in characterization of low mass powder dispersibility.