title: Polymorphism of ceramide 3. Part 1: an investigation focused on the head group of N-octadecanoylphytosphingosine.
abstract: The thermotropic phase behaviour of the ceramide N-octadecanoylphytosphingosine (CER3) was investigated using differential scanning calorimetry, X-ray powder diffraction and FT-IR spectroscopy. CER3 was shown to be a polymorphic substance depending on the crystallisation conditions. Three different solid states were found. The FT-IR results elucidate changes in the hydrogen bonding interactions of the ceramide head group. It was shown that the amide I and the amide II vibration bands are quite sensitive to the phase transitions of CER. There are clear shifts in the band positions of those bands passing the phase transitions. Furthermore, changes were observed in the NH- and OH- stretching region. The study shows that there are strong inter- and intramolecular hydrogen bonds between hydroxy groups in the ceramide head group. There are also strong hydrogen bonds to the amide oxygen as shown by the band positions of the amide vibrations. The H-bonding network and conformation of the head group of CER3 alters due to the phase transitions.
authors.affiliation: Department of Pharmacy, Martin-Luther-University Halle-Wittenberg, Wolfgang-Langenbeck-Str 4, D-06120 Halle Saale, Germany.
authors.forename: Steve
authors.initials: S
authors.lastname: Raudenkolb
authors.forename: Wigand
authors.initials: W
authors.lastname: Hübner
authors.forename: Willi
authors.initials: W
authors.lastname: Rettig
authors.forename: Siegfried
authors.initials: S
authors.lastname: Wartewig
authors.forename: Reinhard H H
authors.initials: RH
authors.lastname: Neubert
mesh_terms: D000577:Amides / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D003460:Crystallization / Q000379:methods*; D003461:Crystallography / Q000379:methods*; D006028:Glycosphingolipids / Q000737:chemistry* / Q000145:classification*; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D000577:Amides; D006028:Glycosphingolipids; C018480:ceramide 3; D010100:Oxygen