Department of Pharmaceutics, University of Minnesota, Minneapolis, Minnesota 55455, USA.
J Pharm Sci. 2010 Feb;99(2):816-27. doi: 10.1002/jps.21876.
Thiamine hydrochloride (Vitamin B(1), THCl) can exist as a nonstoichiometric hydrate (NSH) and as a hemihydrate (HH). NSH can contain up to approximately 1 molar equivalent of water and be dehydrated to an isomorphic desolvate (ID) with minimal change in lattice structure. Crystallographic and spectroscopic techniques were used to characterize the influence of structure and mobility on NSH dehydration. Dehydration was accompanied by lattice contraction, as noted by a decrease in the d-spacings. Dehydration also led to the development of surface cracks parallel to the (101*) and (102*) planes in the NSH single crystal, as observed by hot stage microscopy. Step-wise dehydration of NSH produced gradual shifts in XRPD and SSNMR peaks, indicating that NSH (with approximately 1 mole water) and ID represent the two extremes of a continuum in the hydration state. Variable temperature (13)C SSNMR studies showed that water molecules move rapidly at room temperature within the NSH crystal lattice, and the thiamine molecules transiently exist in distinct hydrated and dehydrated states. It is hypothesized that, despite the lack of continuous hydration channels in the NSH crystal lattice, cooperative deformation of the thiamine molecules allows a nondisruptive departure of water molecules from the lattice during dehydration.
盐酸硫胺素（维生素 B(1)，THCl）可以以非化学计量水合物（NSH）和半水合物（HH）的形式存在。NSH 可以包含多达约 1 摩尔当量的水，并可以脱水形成同构去溶剂化物（ID），而晶格结构的变化很小。使用晶体学和光谱技术来表征结构和迁移性对 NSH 脱水的影响。脱水伴随着晶格收缩，这可以通过 d 间距的减小来证明。脱水还导致 NSH 单晶中与（101*）和（102*）面平行的表面裂纹的形成，这可以通过热台显微镜观察到。NSH 的逐步脱水导致 XRPD 和 SSNMR 峰的逐渐移位，表明 NSH（约 1 摩尔水）和 ID 代表水合状态的连续体的两个极端。变温（13）C SSNMR 研究表明，水分子在室温下在 NSH 晶格中快速移动，而硫胺素分子在短暂的时间内存在于明显的水合和脱水状态。据推测，尽管 NSH 晶格中没有连续的水合通道，但硫胺素分子的协同变形允许水分子在脱水过程中从晶格中无干扰地离开。
