Compaction of and drug release from coated pellets of different mechanical properties

The aim of this work was to relate the mechanical properties of film-coated pellets to their damage received during compaction, and to establish the significance of this damage for the release of a model drug from the resulting tablets. The formulations contained paracetamol and various excipient combinations chosen to provide different mechanical properties of the pellets, which were film-coated with Surelease® at various film thicknesses, and then compacted into tablets using three different compaction pressures. The drug release from the tablets was determined and compared to that of the uncompacted pellets. The compressibility and compactability of the various types of pellets was significantly influenced by the nature of the excipient combinations and binder liquids used to prepare the pellet cores, which also affected the drug release from the tablets. This could be attributed to the different responses of the pellets to compressive and shear stress. The film thickness and the mechanical properties of the film coating were found to be less important for tablet formation, but the film thickness played an important role in controlling the drug release rate from the tablets.