title: Thermal degradation of amorphous glibenclamide.
abstract: A glibenclamide polymorph published by Panagopoulou-Kaplani and Malamataris (2000) [1], obtained by sublimation of amorphous glibenclamide, was analysed. A new interpretation of the data is presented and experimentally confirmed by X-ray powder diffractometry, Fourier transformation infrared spectroscopy, differential scanning calorimetry, and mass spectrometry. The crystals formed during sublimation of amorphous glibenclamide do not represent a glibenclamide polymorph, but a thermal degradation product, namely 1,3-dicyclohexylurea. The reaction mechanism is suggested to be an elimination of cyclohexylisocyanate from glibenclamide. Cyclohexylisocyanate may decompose to carbon monoxide and cyclohexylamine, which may react in an addition reaction with another cyclohexylisocyanate molecule forming 1,3-dicyclohexylurea.
authors: School of Pharmacy, University of Hamburg, Hamburg, Germany.
authors: Sönke
authors: S
authors: Rehder
authors: Albrecht
authors: A
authors: Sakmann
authors: Thomas
authors: T
authors: Rades
authors: Claudia S
authors: CS
authors: Leopold
mesh_terms: D002152:Calorimetry, Differential Scanning / Q000379:methods; D003460:Crystallization / Q000379:methods; D003485:Cyanates / Q000737:chemistry; D004355:Drug Stability; D005905:Glyburide / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013678:Technology, Pharmaceutical / Q000379:methods; D014508:Urea / Q000031:analogs & derivatives / Q000737:chemistry; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D003485:Cyanates; C000536:cyclohexylisocyanate; D014508:Urea; D005905:Glyburide; C000948:1,3-dicyclohexylurea