The impact of solid-state form, water content and surface area of magnesium stearate on lubrication efficiency, tabletability, and dissolution

Magnesium stearate (MgSt) is a widely used pharmaceutical lubricant in tablet manufacturing. However, batch-to-batch variability in hydrate form and surface area can lead to inconsistency in tablet performance. In this work, several unique MgSt samples were studied: traditional monohydrate samples with high surface area, dihydrate forms with high and low surface area, and disordered forms with low and medium water content. The effects of solid-state form and particle properties on lubrication efficiency, tabletability and dissolution were studied for tablets in a model direct compression formulation. It was found that the monohydrate and dihydrate forms had good lubrication efficiency compared to the disordered form, while the disordered form had the best tabletability. The dissolution rate correlated with surface area, where slower dissolution rates corresponded with higher MgSt surface areas. The dihydrate sample with lower surface area had the best performance for this model formulation, in terms of lubrication efficiency, tabletability and dissolution. Overall, it is concluded that the choice of the most appropriate grade of MgSt for a particular formulation depends on a comprehensive evaluation of the impact of MgSt properties on lubrication efficiency, tabletability and dissolution.

硬脂酸镁（Magnesium stearate, MgSt）是片剂生产中应用广泛的药用润滑剂。然而，其水合物晶型与比表面积存在的批间差异，可能导致片剂性能不一致。本研究选取多款特性独特的硬脂酸镁样品开展研究：包括比表面积较高的传统一水合物样品、比表面积高低不一的二水合物晶型，以及含水量低、中等的无定形态样品。本研究针对模型直接压片处方中的片剂，考察了固态晶型与颗粒特性对其润滑效能、可压性及溶出度的影响。研究结果显示，与无定形态样品相比，一水合物与二水合物晶型展现出更优的润滑效能；而无定形态样品的可压性最佳。溶出速率与比表面积呈负相关：比表面积越高，溶出速率越慢。就本次模型处方而言，比表面积较低的二水合物样品在润滑效能、可压性及溶出度三方面均表现最优。综上，本研究得出结论：针对特定处方选择适配的硬脂酸镁品级时，需综合评估其各项特性对润滑效能、可压性及溶出度的影响。