title: Variable-temperature X-ray powder diffraction analysis of the crystal transformation of the pharmaceutically preferred polymorph C of mebendazole.
abstract: Mebendazole 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 degrees 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.
authors.affiliation: School of Pharmacy, University of Louisiana at Monroe, Monroe, Louisiana 71209, USA. devilliers@ulm.edu
authors.forename: Melgardt M
authors.initials: MM
authors.lastname: de Villiers
authors.forename: Rudolf J
authors.initials: RJ
authors.lastname: Terblanche
authors.forename: Wilna
authors.initials: W
authors.lastname: Liebenberg
authors.forename: Erna
authors.initials: E
authors.lastname: Swanepoel
authors.forename: Theo G
authors.initials: TG
authors.lastname: Dekker
authors.forename: Mingna
authors.initials: M
authors.lastname: Song
mesh_terms: D000871:Anthelmintics / Q000032:analysis* / Q000737:chemistry; D003460:Crystallization; D007536:Isomerism; D008463:Mebendazole / Q000032:analysis* / Q000737:chemistry; D015394:Molecular Structure; D013678:Technology, Pharmaceutical / Q000379:methods; D013816:Thermodynamics; D044366:Transition Temperature; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D000871:Anthelmintics; D008463:Mebendazole