The impact of roller compaction and tablet compression on physicomechanical properties of pharmaceutical excipients

Material properties play a significant role in pharmaceutical processing. The impact of roller compaction (RC) and tablet compression on solid fraction (SF), tensile strength (TS) and flexural modulus (FM) of Avicel DG [co-processed excipient with 75% microcrystalline cellulose (MCC) and 25% anhydrous dibasic calcium phosphate (DCPA)], lactose and 1:1 Mixture of the two was studied. Materials were roller compacted at different force and roller type and compressed into tablets over a range of compression pressures (CP). SF, TS and FM were determined for ribbons and tablets. Roller force was a significant variable affecting SF while roller type was not. Both SF and TS of tablets increased with CP with Avicel DG exhibiting greater TS than that of 1:1 Mixture while tablets of lactose had the lowest TS. The TS of tablets decreased exponentially with tablet porosity. Ribbon of Avicel DG had higher TS and lower SF than lactose and greater reworkability. This is attributed to plastic deformation of MCC resulting in high degree of bonding and fragmentation of DCPA that fills the void spaces during tablet compression. The lack of significant increase in SF and low tablet TS for lactose upon compression is likely due to its brittle fragmentation and some elastic recovery as shown by the high FM.