Rapid method for measuring the mechanical properties of pharmaceutical compacts

A rapid technique to measure the mechanical properties of pharmaceutical tablets is presented. The Young's modulus of elasticity and Poisson ratio are determined by fitting the measured transient force, generated by the impact of tablets with a dynamic load cell, by the theoretical force predicted from a Hertzian spring-dashpot model. Results of the method applied to a series of pharmaceutical compacts having different porosities and prepared from different excipient blends, demonstrate good agreement between the calculated force and the measured force. In particular, the Young's modulus and Poisson ratio calculated for a 22% porous microcrystalline cellulose compact are 3.5 GPa and 0.34, respectively. As the total measurement time is less than 100 μs, the technique can be used as an in-line process measurement for manufacturing process control.

The transient force from the impact of model pharmaceutical tablets against a rigid plane is measured by a dynamic load cell and modeled using a Hertzian spring–dashpot (HSD) constitutive relation. From the HSD model, the Young's elastic modulus and Poisson ratio are estimated for compacts of common pharmaceutical excipients over a range of porosities.Figure optionsDownload as PowerPoint slideHighlights
► Simple technique to measure the mechanical properties of pharmaceutical tablets.
► Hertzian spring-dashpot model quantitatively predicts dynamic impact force.
► Measurement time is less than 100 μs.