硬脂酸镁(MgSt)是最常用的辅料对于口腔固体剂型，但具有显着的商业物理化学变异性，可以导致关键产品属性的可变性能。差分扫描量热法（DSC）通常用作质量控制工具来表征MGST，但是对于DSC热图的物理化学相关性，可以使用很少的数据。The main aim of this study was to decipher MgSt’s complex thermotropic behavior using DSC, thermogravimetric analysis, capillary melting point, polarized hot-stage microscopy, and temperature dependent small-angle X-ray scattering (SAXS) and assign physicochemical relevance to the DSC thermograms. Several DSC thermal transitions are irreversible after the first heating cycle of a heat-cool-heat-cool-heat cycle. Interestingly, after the first heat cycle, the complex cool-heat-cool-heat DSC thermograms were highly reproducible and exhibited 6 reversible exothermic–endothermic conjugate pairs. SAXS identified 5 distinct mesophases(at different temperatures with Phase C’ persisting to 250°C. MgSt maintained molecular ordering beyond 276°C and did not undergo a simple melting phenomena reported elsewhere. This research serves as a starting point to design heat-treatment strategies to create more uniform MgSt starting material.