Effect of preparation method on properties of orally disintegrating tablets made by phase transition

In order to evaluate the effect of preparation method on the properties of orally disintegrating (OD) tablets, OD tablets were prepared by compressing a mixture of high melting point sugar alcohol (HMP-SA) and low melting point sugar alcohol (LMP-SA) and subsequent heating. In the direct compression method (DCM) where the LMP-SA was added as a powder, both hardness and disintegration time were increased by decreasing the particle size of the LMP-SA. In the wet granule compression method (WGCM), where the LMP-SA was added as an aqueous binder solution, the tablets became harder with less heating compared to tablets prepared by DCM. Using 1% xylitol as the LMP-SA provided tablets with sufficient hardness when prepared by WGCM, as opposed to DCM where 5% xylitol was necessary to prepare tablets with similar hardness. These results suggest that uniformly distributed LMP-SA on the surface of HMP-SA particles in WGCM might diffuse more easily during the heating process compared to mechanically mixed LMP-SA in DCM, resulting in an increase in tablet hardness even with a short heating time and low content of LMP-SA. In addition, disintegration and hardness stability of the tablets were affected by the LMP-SA content when prepared by WGCM, suggesting that the LMP-SA content should be regulated to assure the stability of OD tablet characteristics.