Dextrins complexes

Upon formulating these relationships, phenols with branched alkyl substituents were not included in the data of a-cyclodextrin systems, though they were included in (3-cyclodextrin systems. In all the above equations, the n term was statistically significant at the 99.5 % level of confidence, indicating that the hydrophobic interaction plays a decisive role in the complexation of cyclodextrin with phenols. The Ibrnch term was statistically significant at the 99.5% level of confidence for (3-cyclo-dextrin complexes with m- and p-substituted phenols. The stability of the complexes increases with an increasing number of branches in substituents. This was ascribed to the attractive van der Waals interaction due to the close fitness of the branched substituents to the (3-cyclodextrin cavity. The steric effect of substituents was also observed for a-cyclodextrin complexes with p-substituted phenols (Eq. 22). In this case, the B parameter was used in place of Ibmch, since no phenol with a branched... 

Calculations based on simple molecular models and the charge density of the layers suggest that sulfopropylated-//-cyclodextrin and carboxyethylated-/3-cyclodextrin are arranged in the interlayer galleries with their conical axis parallel to the layers with a packing structure which is similar to that in crystalline cyclo dextrin complexes, where the molecules are arranged in a brickwork pattern [202]. 

Iron-dextran complex Iron-dextrin complex... 

A ferric hydroxide-dextrin complex is sometimes injected intravenously in cases where oral therapy is impracticable. 

Seo, H., Uekama, K. Enhanced bioavailability of digoxin by -cyclo-dextrin complexation evaluation for sublingual and oral administrations in human. Yakugaku. Zasshi 1989, 109, 778—782. 

Ueno, M., Ijitsu, T., Horiuchi, Y. et al. Improvement of dissolution and absorption characteristics of ubidecarenone by dimethyl-p-cyclo-dextrin complexation. Acta Pharm. Nord. 1989, 2, 99-104. 

Uekama, K., Horiuchi, Y., Kikuchi, M. et al. Enhanced dissolution and oral bioavailabiUty of a-tocopheryl esters by dimethyl-(3-cyclo-dextrin complexations. J. Inclusion Phenom. 1988, 6,167-174. 

Only the triplet and radical reaction rates were affected by the dextrin complexation. 

Uekama, K., Otagiri, M., Sakai, A., et al. "(1985) Improvement in the percutaneous absorption of beclomethasone dipropionate by y-cyclo-dextrin complexation. J. Pharm. Pharmacol. 37 532-535. 

Hoshino, T., Ishida, K., Me, T., et al. (1987) Alleviation in protriptyline-photosensitized skin irritation by di-O-methyl-p-cyclo-dextrin complexation. Int. J. Pharm. 38 265-267. 

Abou-Hamdan, A. Bugnon. P. Saudan, C. Lye, P.G. Merbach, A.E. High-pressure studies as a novel approach in determining inclusion mechanisms Thermodynamics and kinetics of the host-guest interactions for -x-cyclo-dextrin complexes. J. Am. Chem. Soc. 2000. 122 (4). 592-602. 

Thus, the conclusion initially derived only on the basis of quantum-chemical calculations about the possibility of interaction of viral DNA nucleotides with LiCI (I)-l2-a-dextrin complexes, that are part of drugs [17-20], is further conhrmed by the results of complementary experimental investigations. They include UV-spectroscopy study. 

The physico-chemical properties of PGl2Me- p-cyclo-dextrin complex in solid-state have been discussed in this paper ... 

Fig. 7. Host-guest interaction in the permethylated a-cyclo-dextrin complexes with L-mandelic acid (A) and D-mandelic acid (B). Water molecules are shown by full circles. Broken lines indicate hydrogen bonds. The Gl, G2, and G6 residues in the L-mandelic acid complex and the G4, G5, and G6 residues in the D-mandelic acid complex are shaded.

Preparation of Cyclic Dextrins bv Acetylation. Other methods for isolating the cyclic dextrins have been used. An early procedure utilized the differences in solubilities of the dextrin acetates (45). An enzymolysate of starch and macerans amylase was prepared by methods similar to those described above. The cyclic dextrins were precipitated from this enzymolysate with a complexing agent and the dextrin complexes which formed were collected by filtration and air-dried. The mixture of dextrins was acetylated with acetic anhydride in pyridine. A preferential crystallization of the dextrin derivatives was used to separate the derivatives and the individual dextrin acetates were obtained. Deacetylation of the derivatives is required to obtain the crystalline dextrins. 

---