Variations in compaction behaviour for tablets of different size and shape, revealed by small-angle X-ray scattering.

Local variations in compaction behaviour were investigated, for specimens of different shapes and thickness, comparing predictions from finite element (FE) modelling and results from a recently developed method using small-angle X-ray scattering (SAXS). Good agreement was generally obtained between these methods, in terms of the variations of density, compaction strain and principal strain direction within the specimens examined. The combination of SAXS and FE methods appeared particularly suitable for studying pharmaceutical tablets, revealing effects (such as nano-strain of intragranular morphology and strain direction) that are not easily observed by other methods, and which may have significant effects on tablet integrity or swelling and drug delivery characteristics.