Stephenson G A, Groleau E G, Kleemann R L, Xu W, Rigsbee D R
Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, USA.
J Pharm Sci. 1998 May;87(5):536-42. doi: 10.1021/js970449z.
The objective of this work was to investigate a common but poorly understood category of crystalline organic substances: isomorphic desolvates. When solvent is lost from a crystal lattice but the lattice retains its three-dimensional order, a lattice is created which is in a high-energy state relative to the original solvate structure. The desolvated lattice can reduce its internal energy by either resorbing solvent or by relaxation processes which increase the packing efficiency of the solid by reducing the unit cell volume. In the following paper, solid-state properties of isomorphic desolvates of cephalexin, cefaclor, erythromycin A, and spirapril hydrochloride hydrates are investigated. The hygroscopicity of the compounds are evaluated using a vacuum moisture balance, and structural relaxation is measured using a combination of X-ray powder diffraction and isothermal microcalorimetry. The study results are explained in terms of Kitaigorodski's close packing principle.
同构去溶剂化物。当溶剂从晶格中流失但晶格保持其三维有序性时，就会形成一种相对于原始溶剂化物结构处于高能态的晶格。去溶剂化晶格可以通过重新吸收溶剂或通过松弛过程来降低其内能，这些松弛过程通过减小晶胞体积来提高固体的堆积效率。在接下来的论文中，研究了头孢氨苄、头孢克洛、红霉素A和盐酸螺普利水合物的同构去溶剂化物的固态性质。使用真空水分天平评估化合物的吸湿性，并结合X射线粉末衍射和等温微量热法测量结构松弛。研究结果根据 Kitaigorodski 的紧密堆积原理进行了解释。
