Spray dried products - Characterization of particle morphology

Samples of industrial and pilot plant spray-dried materials were obtained from various manufacturers together with details of drying conditions and feed specifications. The samples were subjected to qualitative and semi-quantitative examination to identify structural and morphological features. The results were interpreted in terms of bulk physical properties and related to drying conditions. Three distinct categories of particle morphology were identified, namely, crystalline, skin-forming and agglomerate. Selected properties such as powder flowability, particle and bulk density, particle size and particle friability were shown to have a direct relationship to morphological structure.