Powder compactibility is one of the key parameters in the pharmaceutical tabletting process and is affected by both the primary particle properties and the process design. The key particle properties that affect its compaction characteristics are the particle size distribution and particle shape, its crystal habit and the particle mechanical properties such as fracture toughness, elasticity, hardness etc.

In this paper, ibuprofen, a non-steroidal drug that is needle-shaped and widely used as an anti-inflammatory analgesic was chosen as a model material to assess the effect of particle properties on its compaction characteristics. The effect of particle properties such as particle size and size distribution and admixing magnesium stearate to ibuprofen were studied in detail. The key compaction parameters measured were the tablet out-of -die porosity and its tensile strength. It was found that both the tablet out-of-die porosity and its tensile strength increase with the decrease of particle size. Although adding magnesium stearate was found to be very beneficial for powder flow, the table mechanical properties such as the tensile strength were reduced significantly.