title: Physicochemical properties and X-ray structural studies of the trigonal polymorph of carbamazepine.
abstract: The trigonal polymorph of carbamazepine (alpha-carbamazepine) was obtained by crystallization from a number of solvents. It was characterized by means of differential scanning calorimetry, thermogravimetric analysis, infrared spectroscopy, X-ray power diffraction, thermal microscopy, and powder and intrinsic dissolution rates. The crystal and molecular structures were determined by single-crystal, three-dimensional X-ray analysis. A comparison is drawn between the physicochemical properties of the monoclinic (beta) and trigonal (alpha) forms. Structural features of carbamazepine occurring in these forms and in the acetone solvate are compared. Substantial differences were detected between the two polymorphic forms with regard to infrared and differential scanning calorimetry data, thermomicroscopical behavior, morphology, and molecular conformation.
authors.affiliation: Faculty of Pharmacy, University of Potchefstroom for C.H.E., Republic of South Africa.
authors.forename: M M
authors.initials: MM
authors.lastname: Lowes
authors.forename: M R
authors.initials: MR
authors.lastname: Caira
authors.forename: A P
authors.initials: AP
authors.lastname: Lötter
authors.forename: J G
authors.initials: JG
authors.lastname: Van der Watt
mesh_terms: D000927:Anticonvulsants / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002220:Carbamazepine / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D012995:Solubility; D013055:Spectrophotometry, Infrared; D014961:X-Ray Diffraction
chemical_list: D000927:Anticonvulsants; D002220:Carbamazepine