Universität zu Köln

Eguchi, Kazuya, Niether, Doreen ORCID: 0000-0002-8496-4215, Wiegand, Simone ORCID: 0000-0001-6333-1956 and Kita, Rio ORCID: 0000-0002-9683-5840 (2016). Thermophoresis of cyclic oligosaccharides in polar solvents. Eur. Phys. J. E, 39 (9). NEW YORK: SPRINGER. ISSN 1292-895X

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Abstract

Cyclodextrins are cyclic oligosaccharides which are interesting as drug delivery systems, because they can be used as containers for pharmaceutical substances. We studied the Ludwig-Soret effect of alpha-, beta-, gamma- and methyl-beta-cyclodextrin in water and formamide by infrared thermal diffusion forced Rayleigh scattering (IR-TDFRS). In water the Soret coefficient, S-T, of alpha-, beta- and gamma-cyclodextrin increases with increasing temperature and shows a sign change from negative to positive around T = 35 degrees C, while S-T of methyl-beta-cyclodextrin is positive in the entire investigated temperature. In formamide S-T-values of all cyclodextrins coincide and show a slight decrease with temperature. We discuss the obtained results and relate the S-T-values to the different hydrogen bonding capabilities of the cyclodextrins and the used solvents. It turns out that the change of S-T with temperature correlates with the partition coefficient, log P, which indicates that more hydrophilic substances show a more pronounced temperature sensitivity of S-T. Additionally we obtained a surprising result measuring the refractive index contrast factor with temperature, (partial derivative n/partial derivative T)(c,p) of cyclodextrins in formamide, which might be explained by a complex formation between cyclodextrins and formamide.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Eguchi, Kazuya UNSPECIFIED UNSPECIFIED UNSPECIFIED Niether, Doreen UNSPECIFIED orcid.org/0000-0002-8496-4215 UNSPECIFIED Wiegand, Simone UNSPECIFIED orcid.org/0000-0001-6333-1956 UNSPECIFIED Kita, Rio UNSPECIFIED orcid.org/0000-0002-9683-5840 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-262042
DOI:	10.1140/epje/i2016-16086-5
Journal or Publication Title:	Eur. Phys. J. E
Volume:	39
Number:	9
Date:	2016
Publisher:	SPRINGER
Place of Publication:	NEW YORK
ISSN:	1292-895X
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Physical Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language FORCED RAYLEIGH-SCATTERING; THERMAL-DIFFUSION; REFRACTIVE-INDEX; CYCLODEXTRIN COMPLEXES; TEMPERATURE-DEPENDENCE; NONIONIC SURFACTANTS; CRYSTAL-STRUCTURES; GRATING TECHNIQUE; SORET; MIXTURES Multiple languages Chemistry, Physical; Materials Science, Multidisciplinary; Physics, Applied; Polymer Science Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/26204