Assessment of distribution of pellets in tablets by non-destructive microfocus X-ray imaging and image analysis technique
In this study, potassium chloride (KCl) containing matrix pellets were compressed into tablets using powder or pellet form of partially spray dried lactose as filler-binder excipient. The spatial distribution of potassium chloride pellets within the tablets was examined by non-destructive microfocus X-ray imaging (MFX) and image analysis technique. The KCl content of the tablets was determined by conductivity measurement and these values were compared to the average gray values of the MFX images calculated by image analysis software. A linear relationship has been showed between the KCl content predicted from average gray values of the MFX images and the actual KCl content measured by conductometry. The non-destructive MFX method was capable to characterize the pellet distribution as well as the pellet content of multiparticulate. Based on the observed spatial distribution of KCl pellets within the tablets made using lactose pellets or powder for direct compression as filler excipients the difference in homogeneity was not remarkable besides the applied blending method.