Cyclodextrin inclusion effects

Our studies of the molecular host-guest interactions are primarily directed toward understanding the cyclodextrin inclusion effect on die molecular motion, local electron density and molecular relaxkioa... 

Diclofenac sodium is an example where cyclodextrin inclusion has a positive effect on the photostability of the gel formulation. Spray dried diclofenac-cyclodextrin complexes in hydroxyethylcellulose gels showed, after three hours of irradiation. 

Kamiya M., Nakamura K., and Sasaki C. (1994) Inclusion effects of cyclodextrins on photodegradation rates of parathion and paraoxon in aquatic medium [iic]. Chemo-sphere 1961—1966. 

Detailed analyses of intramolecular structures are possible. Comparison of NMR and fluorescence data shows meso- and racemic diastereoisomers are found from 2,4-di(2-pyrenyl)pentane 24 jhe polarization of monomer and excimer of 4,9, disubstituted pyrenes have been measured in nematic liquid crystals 25 Quenching of pyrene fluorescence by alcohols in cyclodextrin inclusion complexes has also been studied in detail 26 Solvent effects on the photophysical properties of pyrene-3-carboxylic acid has been used to measure the pJJ, in different solvents 27 Geminate recombination in excited state proton transfer reactions has been studied with... 

Two studies have been reported on azobenzenes 2, 2 5 4 jp case of the sterically hindered 0,0,0substituted azobenzines the effect of exciting lower M n, tt ) and higher (ir, ir ) states has been studied25. in cyclodextrin inclusion complexes of azobenzene there is partial blockage of rotational motion about the N=N bond25. ... 

Capillaries with chiral polymer coatings have been applied in CE for resolution of enantiomers. Possibly because of its inclusive effect, cyclodextrin seems to be an effective chiral selective agent when bonded to a fused-silica capillary surface. In this case, the purpose of the modification is to induce interactions with the chiral material on the surface. Certainly, the cyclodextrin moiety lowers EOF like other wall modifications because it diminishes the number of silanols. The lower EOF allows for slower migration of the solute through the column and, hence, more time for interaction with the chiral selector. The diminished number of silanols also results in less nonspecific interactions with the fused-silica surface, which would tend to degrade the enantiomeric separation. 

Uekama, K. Cyclodextrin inclusion compounds effects on stability and bio-pharmaceutical properties. In Topics in Pharmaceutical Sciences (Breimer, D. D., Speiser, P, Eds). Elsevier Amsterdam, 1987, pp. 181-194. 

Sortino, S., Giuffrida, S., De Guidi, G., Chillemi, R., Petralia, S., Marconi, G., Condorelh, G., and Sciuto, S. (2001) The photochemistry of flutamide and its inclusion complex with 3-cyclodextrin. Dramatic effect of the microenvironment on the nature and on the efficiency of the photodegradation pathways, Photochem. Photobiol., 73, 6-13. 

Catena GC, Bright FV. Thermodynamic study on the effects of P-cyclodextrin inclusion with anilinonaphthalenesulfonates. Anal Chem 1989 61 905-9. 

Compared to the extensive studies on cyclodextrin inclusion complexes in solution,67 corresponding studies in the gas phase are still very limited.73,74 During the solution-to-vacuum transfer in the mass spectrometer, the effect of solvent and counter ions no longer occurs. A main consequence is that electrostatic interactions might become dominant, resulting in unspecific binding between host and... 

Esters can be cleaved by template catalysts that use a metal ion as both a binding group and part of the catalytic system [79-81]. However, metal ion catalysis has also been extended to cases in which the principal substrate binding involves cyclodextrin inclusion indeed, the first catalyst described as an artificial enzyme was. such an example [82]. A cyclodextrin dimer 47 with a bound metal ion between the two cyclodextrins is a particularly effective hydrolytic catalyst for esters that can bind into both cyclodextrin units (Scheme 6-20) [83, 84]. 

Zhang, A and W Liu (2008). Inclusion effect of alpha-cyclodextrin on chemical degradation of malathionin water. Archives of Environmental Contamination and Toxicology, 54, 355-362. 

Bhandari B.R., DArcy B.R., and Le Thi Bich L., 1998. Lemon oil to P-cyclodextrin ratio effect on the inclusion efficiency of P-cyclodextrin and the retention of oil volatiles in the complex. Journal of Agricultural... 

ABSTRACT. The photodimerization of 2-anthracenesulfonate in water was accelerated in the presence of 3- and y-cyclodextrins (CyDs). While four configurational isomers of the photodimer were obtained in the presence of Y-CyD with similar ratio of the yields to that in the host-free solution, only one of the isomers was obtained in the presence of 3-CyD. The results were explained by the formation of two guest-one host inclusion complex in the former case and of two guest-two host inclusion complex in the latter. No evidence of an inclusion complex with a-CyD was obtained. The inclusion effects of CyD on the photodimerization of other water-soluble anthracenes were also examined. 

Cyclodextrins have had valuable industrial uses for a considerable time, particularly as agents to bind or release volatile molecules. Accurate predictions concerning the selectivity and stability of cyclodextrin-guest complexes are therefore of considerable interest both academically and practically." MD was used to simulate cyclodextrin hydrates" as a test of the applicability of the GROMOS program package to systems beyond proteins and nucleic acids. Other early MD simulations focused on interactions with guests such as enantiomers of methyl-2-chloropropionate. Comparisons between calculated thermodynamic properties for complexes formed by O -cyclodextrin with para-substituted phenols and the results of MM simulations led to improvements in force fields that described the interactions. MM2 simulations were used to support NMR data for the -cyclodextrin inclusion complex with benzoic acid. " The well-known catalytic effect of cyclodextrins has been modeled. For example, the relative rate increase of hydrolysis of S over R phenyl ester stereoisomers in the presence of -cyclodextrin... 

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