Supramolecular elucidation of the quality attributes of microcrystalline cellulose and isomalt composite pellet cores

•MCC/isomalt inert cores of spherical shape were prepared.•Macro- and microstructural characteristics of MCC/isomalt composites were studied.•Non-covalent interaction was confirmed with PALS and NIR between the MCC-isomalt.•PALS enabled the design of pellets of required physical attributes. The major objective of this study was to disclose the relationships between the physical quality attributes and supramolecular structure of novel composite pellet cores containing microcrystalline cellulose (MCC) and isomalt in different ratios. The novel composite pellet cores were manufactured by an extrusion/spheronisation process. The micro or supramolecular structure of pellets was tracked by positron annihilation lifetime spectroscopy (PALS) based on the o-Ps lifetime values. The results indicate a correlation between the examined macro and microstructural properties of the inert cores. The higher free volume holes indicated by the higher o-Ps lifetime values resulted in a more mobile micro- and supramolecular structure of MCC cores thus increasing the plastic deformation and the tensile strength of the cores. A physical interaction was found between the microcrystalline cellulose and isomalt which supports the osmotic effect of the water soluble sugar alcohol in the composite pellet cores regarding drug release.