De Villiers, Melgardt M.Terblanche, Rudolf J.Liebenberg, WilnaSwanepoel, ErnaDekker, Theo G.2014-05-092014-05-092005De Villiers, M.M. et al. 2005. Variable-temperature X-ray powder diffraction analysis of the crystal transformation of the pharmaceutically preferred polymorph C of mebendazole. Journal of pharmaceutical and biomedical analysis, 38(3):435-441. [https://doi.org/10.1016/j.jpba.2005.01.025]9731-70851873-264Xhttp://hdl.handle.net/10394/10498https://www.sciencedirect.com/science/article/pii/S0731708505000749https://doi.org/10.1016/j.jpba.2005.01.025Mebendazole is a common benzimidazole anthelmintic that is water insoluble. It is reported to exist in three different polymorphic forms in the solid state, i.e. polymorph A, B and C. Form C is the pharmaceutically preferred form because of its increased aqueous solubility. This paper deals with the use of variable-temperature X-ray powder analysis (VTXRPD) to study the transformation of Form C. Results showed that Form C was stable and transformed to the more stable polymorph A at high temperature (>180 °C). This transformation is a first-order process with activation energy of 238 ± 16 kJ/mole. Further studies showed that compression did not cause any significant changes in the crystal structure of polymorph C.enMebendazolePolymorph transformationVariable-temperature X-ray powder diffractionArticle