Particle size and shape play important roles in the powder industries, including the pharmaceutical industry. It is widely accepted that the flow properties of most powder-based products are closely related to the size distribution of the fine particles. Cohesion forces act between the particles, and friction forces between the particles and the walls of a funnel, which influence the flow properties. The higher the friction/cohesion force, the poorer the flowability, but free flow is essential during capsule filling or tableting processes. Good flowability is especially important during the manufacturing of minitablets where the diameter of dies is very small and the filling time is also very short. The development of a dosage form is based on a factorial design, but the flow properties are influenced by a number of parameters, including particle size, roundness, roughness, flow time and angle of repose. Accordingly, we looked for a cohesion coefficient which takes these parameters into account and can easily be used in the design process, and set out to determine the relationship between the small diameter of the die, which is a critical parameter in the compression of minitablets, and the cohesion coefficient. In this work, different forms of commercial sorbitol were chosen as model material: sorbitol is frequently used as a filler in the preparation of capsules and tablets. The morphological parameters and particle size distributions were tested. Different size fractions were separated by sieving, their powder rheological parameters were determined and the cohesion coefficients were calculated. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.