Polymorphism of ceramide 6: a vibrational spectroscopic and X-ray powder diffraction investigation of the diastereomers of N-(α-hydroxyoctadecanoyl)-phytosphingosine
摘要:
A preparative chromatographic method was developed for the quantitative isolation of the diastereomers of synthetic N-(alpha-hydroxyoctadecanoyl)-phytosphingosine (DL-CER6). The (L)- and the (D)-compound were studied each by means X-ray powder diffraction, FT-Raman and FT-IR spectroscopy. The diastereomers exhibit different thermotropic polymorphism. Three lamellar crystalline and a lamellar liquid crystalline phase were found for L-CER6. The natural occurring D-CER6 forms an La phase with a larger repeating distance than the L-CER6. The two lamellar crystalline phases of the D-compound have a significant larger dimension than those of the L-compound. The addition of water lowers the phase transition temperatures but does not induce structural changes such as incorporation into the lamellar sheets. (C) 2004 Elsevier Ireland Ltd. All rights reserved.