A model to simultaneously evaluate the compressibility and compactibility of a powder based on the compression ratio

The present study aimed to establish a new model to evaluate the compressibility and compactibility of materials simultaneously. Eighteen types of pharmaceutical excipients were studied via direct compaction. The model was established as CR = y₀ + Ae^-bP, r² ≥ 0.9684 (where CR is the compression ratio and P is the compaction force and y₀, A, b is constant). The physical meaning of y₀ and b were studied in the model. The results show that y₀ has a strong correlation with the mean yield pressure (Py, r = 0.609, P < 0.01), which is the evaluation parameter of material compressibility. b has a strong correlation with the evaluation parameter of material compactibility, such as the slope of the tensile strength versus compaction force (k_A, r = 0.780, P < 0.01) and the tensile strength versus porosity (Ryshkewitch-Duckworth equation) (k_R, r = 0.658, P < 0.01). The results of model experiments (r = 0.767, 0.895, and 0.756), literature, and repeatability verification demonstrated that the main parameters y₀ and b in the established model have good applicability and repeatability. Therefore, the newly established model is reliable for evaluating both the compressibility and the compactibility of powders. The model provides support for further research into powder properties and tablet preparation.