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Analytica Chimica Acta 468 (2002) 161-170

Differentiating geometrical isomers of retinoids and controlling their photo-isomerization by complexation with cyclodextrins. Analytica Chimica Acta 468 (2002) 161-170. Cyclodextrins. Cyclic oligosaccharides Composed of D(+)glucopyranose units Hollow, torus-shape cavity

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Analytica Chimica Acta 468 (2002) 161-170

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  1. Differentiating geometrical isomers of retinoids and controlling their photo-isomerization by complexation with cyclodextrins Analytica Chimica Acta 468 (2002) 161-170

  2. Cyclodextrins Cyclic oligosaccharides Composed of D(+)glucopyranose units Hollow, torus-shape cavity Cylinders with a hydrophilic exterior and a hydrophobicinterior

  3. Cyclodextrins Differenttypes: α-cyclodextrin : six sugar ring molecules β-cyclodextrin : seven sugar ring molecules γ-cyclodextrin: eight sugar ring molecules

  4. Structure of α-CD

  5. Structure of γ-CD Structure of β-CD

  6. Cyclodextrins They form inclusion complexes with a variety of molecules. Insertion of a hydrophobic guest in aqueous solutions of cyclodextrins leads to complexation which no covalent bonds are broken or formed.

  7. Applications of Cyclodextrins in Drug delivery technology To improve the physical and chemical properties of drugs To reduce the side effects of drugs To enhance the bio-availibility of poorly soluble drugs

  8. Applications of Cyclodextrins in Food industry To stabilize flavors and fragrances To mask undesired tastes in the food and cosmetic industries

  9. Applications of Cyclodextrins Chemistry Separation techniques HPLC and … Increasing the solubility and the stability of the analytes and therefore sensitivity of the detection of these analytes Increasing or decreasing the rate of a variety of reactions …

  10. Retinoids Very significant biological molecules due to : - Their role in the vision process (retinal) - As vitamins (retinol and its esters) - Their influence in the cell growth (retinoic acid , …)

  11. All trans retinal

  12. H-NMR spectra of the pure β-CD solution (C=1.0 x 10-2 M)

  13. H-NMR spectra of the complex of all-trans-retinal/β-CD at concentrations 4.0 x 10-3 and 1.0 x 10-2 M respectively.

  14. Chemical shifts in H-NMR

  15. Stoichiometry determination

  16. Association constants determination

  17. 9-Cis retinal

  18. Effect of the inclusion process on the photo-isomerization of retinoids

  19. Ethanolic solution

  20. All-trans-retinal

  21. All-trans-retinoic acid

  22. Thanks

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