Flowability measurements of pharmaceutical powder mixtures with poor flow using five different techniques

Four different tablet formulations for direct compression with poor flow properties were tested regarding flowability using five different techniques: Hausner ratio, avalanching behavior, powder rheometer, uniaxial tester, and Jenike tester. In addition, the behavior of three of the formulations during emptying of the mixer and tableting was observed and compared to the results of the flowability measurements. The rank order correlation of the formulations was generally the same with all techniques. The flow properties measured by the different techniques reflected the behavior during processing of the powder mixtures.