Non-destructive evaluation of the mechanical properties of pharmaceutical solid dosage forms with teraHertz imaging

In this work we show that TeraHertz imaging can non- destructively investigate a series of pharmaceutical tablets to help understand the role of inhomogeneities and their relationship to mechanical properties. A number of deliberately stressed tablets were investigated; tablets were produced with different physical properties with a compaction simulator. We show that THz imaging can be used to obtain information on density variations within tablets that are associated withchanging mechanical properties, which, in turn are shown to be associated with internal inhomogeneities. Such images provide the means to non-destructively investigate the role of die separation and press speed on tablet manufacture and provide an understanding of critical design parameters. The investigation of different press conditions and blends demonstrate that the friability and hardness tests measure properties that are characteristic of features present at different depths. We believe that THz imaging provides a useful means to understand critical parameters that influence the mechanical behaviour of tablets.