Cyclodextrins (CD) are cyclic oligosaccharides composed of six to more than sixty
glucose units. Large-ring cyclodextrins (LR-CD) are novel CD comprised of more than eight
glucose units with cavity structures and sizes different from that of commercially available
CD<sub>6</sub> – CD<sub>8</sub>. LR-CD may offer unique molecular recognition properties and can be produced
biocatalytically from starch using cyclodextrin glucanotransferase (CGTase, E.C. 2.4.1.19) in
a short reaction time. LR-CD were isolated from glucose, CD<sub>6</sub> – CD<sub>8</sub> and other compounds by
complexation of CD<sub>6</sub> – CD<sub>8</sub> as well as precipitation techniques. The yield of LR-CD (degree
of polymerization from 9 to 21) was optimized using central composite design. Addition of
polar organic solvents to the synthesis resulted in higher yields of LR-CD. LR-CD composed
of 9 to 21 glucose units were successfully separated using reversed-phase of ODS-AQ
chromatography and normal-phase of polyamine II chromatography. Maintaining optimized
reaction conditions aided in a high yield of CD<sub>9</sub>; it could be separated with reasonable yield
using a single step of polyamine II chromatography. A co-grinding method helped to obtain
higher solubilization levels of glibenclamide, vitamin A acetate and vitamin D<sub>3</sub> in CD<sub>13</sub>, CD<sub>10</sub>
and CD<sub>11</sub>, respectively when compared to other CD. Vitamin K<sub>1</sub> was solubilized in distilled
water with CD<sub>6</sub> – CD<sub>13</sub> using a co-precipitation method. When compared with other CD, CD<sub>9</sub>
was seen to be the best solubilizer. The analysis of complexes using ESI MS showed
spironolactone and glibenclamide complexed with CD<sub>9</sub> and CD<sub>13</sub>, respectively.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:19091 |
| Date | 26 January 2009 |
| Creators | Mokhtar, Mohd Noriznan |
| Contributors | Zimmermann, Wolfgang, Platzer, Bernd, Sträter, Norbert, Technische Universität Chemnitz |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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