A dissertation submitted to the Department of Technical Thermodynamic, Faculty of Mechanical Engineering, Chemnitz University of Technology, Chemnitz, Germany, 2009. 160 Pages, 80 Figures, 23 Tables, 105 References
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 CD6 β CD
8. 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, CD6 β CD8 and other compounds by complexation of CD6 β CD8 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 CD9; 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 D3 in CD13, CD10 and CD11, respectively when compared to other CD. Vitamin K1 was solubilized in distilled water with CD6 β CD13 using a co-precipitation method. When compared with other CD, CD9 was seen to be the best solubilizer. The analysis of complexes using ESI MS showed spironolactone and glibenclamide complexed with CD9 and CD13, respectively.