This study was performed to systematically investigate the polymorphism of shikimic acid. Through optimizing the recrystallization solvent, solvent volume, recrystallization temperature, time and pressure, three crystal forms were discovered and prepared. The differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray powder diffraction (PXRD) and infrared spectrometry (IR) were used to characterize these solid states. Furthermore, the influencing factor experiments were used to explore the stability of these polymorphisms and the transformation among them. Three new polymorphisms were prepared and identified. The results indicated that only PXRD could identify different polymorphisms and there was no solvent in all three crystal forms. The composition, thermodynamic property and transformation of these crystal forms were described in this work. Furthermore, an effective method for qualitative analysis of these crystal forms was established.
Keywords: detection method; polymorphism; quality control; shikimic acid.
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