Evaluation of a rapid approximation method for the elastic recovery of tablets

The present work evaluates the usefulness of “in die” elastic recovery descriptors as an indicator of tabletability. Tablet elastic recovery (“in die” and “out-of-die”) with respect to applied compression speed and dwell time were evaluated by applying 22-full factorial design with one centre point. Flat tablets of constant true volume were compressed on a compaction simulator at constant pressure. “In die” and “out-of-die” elastic recoveries were calculated by using obtained respective continuous compression profiles and measured tablet dimensions (height and diameter) at a constant humidity. Linear relationship between “in die” and “out-of-die” elasticity descriptors was found. The qualitative and quantitative relationships of “in die” elasticity descriptors with tensile strength (TS) was evaluated by principal component analysis (PCA) and partial least square regression (PLS). These analyses showed that “in die” elasticity descriptors like Heckel yield pressure of elasticity and immediate axial recovery (IAR) have significant negative influence on TS. The present study shows that the experimentally easier accessible “in die” elastic recovery method can be used as an indicator of elasticity of various pharmaceutical tableting materials with respect to tabletability.