Comparative studies of different modifications of calcium valproate

Comparison of Solid-State 13C NMR Spectroscopy and Powder X-ray Diffraction for Analyzing Mixtures of Polymorphs of Neotame

“…Many techniques, such as microscopic methods, thermal analytical techniques, and spectroscopic methods, have been used to study polymorphism. Microscopic methods include hot-stage microscopy − and scanning electron microscopy. − Thermal techniques are frequently employed and include thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry, and solution calorimetry. , Spectroscopic methods of analysis include infrared, − near-infrared, , Raman, , and ultraviolet/visible diffuse reflectance spectroscopy. − Measurements of density , and solubility − are also commonly used. The most powerful technique for determining the existence of polymorphism is single-crystal X-ray diffraction because it provides a detailed description of the crystal structure of a solid phase, including molecular conformation and packing .…”