This study investigates the effect of pneumatic spray drying using a two fluid nozzle on pharmaceutical excipients used in compression analyzing, modifications in the morphology, particle size and particle size distribution. The pharmaceutical excipients selected were classified into three groups according to their solubility in water: excipients that are soluble in water, partially soluble in water, and practically insoluble in water. Both spray drying conditions and properties of the liquid to be atomized were established for each of the excipients studied. The results obtained, in terms of the characterization of particles, were different depending on the excipient and the group to which they belonged. Properties such as flowability and compressibility that pertain to bulk level of solid state are strongly influenced by changes in characteristics at the particle level, such as size, size distribution and morphology of particles, which is the subject of study in this investigation. (C) 2014 Elsevier B.V. All rights reserved.