Influence of Powder Mixing Efficiency on the Quality Attributes of Pharmaceutical Tablets

Powder mixing is a critical step in pharmaceutical manufacturing, as the uniform distribution of an active pharmaceutical ingredient (API) affects the quality of the final dosage form. This study investigated the relationship between powder mixing performance and tablet quality attributes using sodium naproxen as a model API with limited flowability. Powder mixtures were prepared in a V-type blender, and the mixing index evolution was evaluated at different rotational speeds. Tablets were subsequently produced either by direct compression or by pan granulation followed by compression, and their critical quality attributes, including tablet mass, thickness, crushing strength, abrasiveness, and API content variability, were evaluated. The mixing index rapidly increased during blending and reached high values for all investigated conditions; however, similar mixing efficiency did not result in equivalent tablet properties. Directly compressed tablets exhibited higher crushing strength, lower abrasiveness, and lower API content variability compared with tablets obtained after pan granulation. The results demonstrated that the powder processing route had a stronger influence on final tablet performance than differences in mixing speed within the investigated range. The combination of mixing index evaluation with tablet quality assessment provides a comprehensive approach for understanding the influence of powder processing conditions on pharmaceutical tablet performance.