Abstract

Preformulation studies like storage, transfer, fluidisation, and compaction, are subject to the excellent flowability of the powder. It is often required for proper operational management and consistent design of industrial processes. Two basics methods have been utilised to characterise the flow behaviour of bulk solids. Traditionally, powder has been evaluated in terms of simple and straight forward techniques like Hausner’s ratio, Carr’s index, bulk density, and angle of repose. Despite that, the results obtained in the traditional method lack predictability, reproducibility, sensitivity, and the actual association between the resulting data and flow behaviour. Henceforth the results varied for weight variation, content uniformity, and dissolution, etc. during the preparation of final dosage forms. To overcome these limitations of the traditional methods, the advanced techniques are being utilised to explore micro properties like the angle of internal friction, bulk density, flow function, yield loci, powder rheometry under precisely controlled conditions of consolidation stress. Ultimately these techniques help to design, choose suitable excipients, reduce time along with cost, and improve the health of society. This review focuses on some of the most commonly applied methods used in traditional and advanced shear cell testing techniques to measure the flow of powders.