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  • 1
    Electronic Resource
    Electronic Resource
    Complex formation of hexakis(2,3,6-tri-O-methyl)-α-cyclodextrin with substituted benzenes in aqueous solution (1988)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 6 (1988), S. 135-142 
    Details
    ISSN: 1573-1111
    Keywords: Permethylated α-cyclodextrin ; induced circular dichroism ; inclusion complex ; host-guest interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The complex formation of hexakis (2,3,6-tri-O-methyl)-α-cyclodextrin with substituted benzenes has been investigated by circular dichroism (CD) spectroscopy. The sign and shape of the CD spectra markedly differ from the spectra of corresponding α-cyclodextrin complexes because of the distorted conformation of the host molecule and/or the difference in the geometry of the host-guest interaction. Enthalpy and entropy changes of the complex formation are determined by using the CD band intensities measured at various temperatures and host concentrations. Negative values of ΔH and ΔS indicate that the hydrophobic interaction is not the major driving force for the complex formation. The guest molecule is suggested to be tightly bound within the host cavity through the induced-fit conformational change of the host molecule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00663046
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  • 2
    Electronic Resource
    Electronic Resource
    Crystal structures of heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin complexes with (R)- and (S)-Flurbiprofen (1988)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 6 (1988), S. 443-460 
    Details
    ISSN: 1573-1111
    Keywords: Methylated cyclodextrin ; inclusion complex ; host-guest interaction ; chiral recognition ; crystal structure ; Flurbiprofen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Hepatakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TM-β-CDx) forms crystalline complexes with (R)-Flubiprofen (R-FP), C63H112O35C15H13O2F·H2O, and (S)-Flurbiprofen (S-FP), C63H112O35C15H13O2F. The crystal structures were determined by X-ray analysis. Crystals of both compounds are orthorhombic and the space group isP212121 with cell dimensions:a=15.092(2),b=21.714(3), andc=28.269(4) Å for theR-FP complex, anda=15.271(2),b=21.451(3) andc=27.895(3) Å for theS-FP complex. The macrocyclic ring of TM-β-CDx is markedly distorted because of the inability to form intramolecular hydrogen bonds and the steric hindrance involving methyl groups. In both complexes, the phenyl group is inserted into the host cavity from the O(2), O(3) side, which is wider than the O(6) side. The biphenyl moiety ofR-FP is fixed in theR-configuration within the host cavity. The phenyl group ofS-FP is disordered, andR-andS-configurations are statistically distributed with equal probability. TM-β-CDx molecules are stacked along theb axis to form a column structure. The TM-β-CDx molecule is laterally shifted with respect to the column axis, and a half of the guest molecule protrudes outside from the crevis of the column. The carboxyl group ofR-FP forms a hydrogen bond with water located outside the host cavity, while the carboxyl group ofS-FP is hydrogen-bonded to an oxygen atom of an adjacent TM-β-CDx.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00660743
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  • 3
    Electronic Resource
    Electronic Resource
    Species differences for stereoselective hydrolysis of propranolol prodrugs in plasma and liver (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 9 (1997), S. 661-666 
    Details
    ISSN: 0899-0042
    Keywords: esterase ; O-acyl-propranolol ; substrate specificity ; structure activity relationship ; in vitro degradation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Species differences and substrate specificities for the stereoselective hydrolysis of fifteen O-acyl propranolol (PL) prodrugs were investigated in pH 7.4 Tris-HCl buffer and rat and dog plasma and liver subfractions. The (R)-isomers were preferentially converted to propranolol (PL) in both rat and dog plasma with the exception of isovaleryl-PL in rat plasma, although the hydrolytic activities of prodrugs in rat plasma were 5-119-fold greater than those in dog plasma. The prodrugs with promoieties (C(=O)CH(R)CH3) based on propionic acid showed marked preference for hydrolysis of the (R)-enantiomers in plasma from both species (R/S ratio 2.5-18.2). On the other hand, the hepatic hydrolytic activities of prodrugs were greater in dog than rat, especially in cytosolic fractions. The hydrolytic activity was predominantly located in microsomes of the liver in rat, while the cytosol also contributed to hepatic hydrolysis in dog. Hepatic microsomal hydrolysis in dog showed a preference for the (R)-isomers except acetyl- and propionyl-PL. Interestingly, in rat liver all types of prodrugs with substituents of small carbon number showed (S)-preference for hydrolysis. The hydrolyses of (R)- and (S)-isomers of straight chain acyl esters in rat liver microsomes were linearly and parabolically related with the carbon number of substituents, respectively, while these relationships were linear for both isomers in dogs. Chirality 9:661-666, 1997. © 1997 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Stereoselective disposition of flurbiprofen from a mutual prodrug with a histamine H2-antagonist to reduce gastrointestinal lesions in the rat (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 8 (1996), S. 494-502 
    Details
    ISSN: 0899-0042
    Keywords: hydrolysis ; carboxylesterase ; bioconversion ; plasma concentration ; pharmacokinetics ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The in vitro and in vivo stereoselective hydrolysis characteristics of the mutual prodrug FP-PPA, which is a conjugate of flurbiprofen (FP) with the histamine H2-antagonist PPA, to reduce gastrointestinal lesions induced by FP were investigated and compared with those of FP methyl ester (rac-FP-Me) and FP ethyleneglycol ester (rac-FP-EG). The rac-FP derivatives were hydrolyzed preferentially to the (+)-S-isomer in plasma and to the (-)-R-isomer in liver and small intestinal mucosa. Interestingly, in the gastric mucosa, the stereoselectivity of hydrolysis of (-)-R-FP-PPA was opposite from that of rac-FP-Me and rac-FP-EG, which suggested that the stereoselective hydrolysis of FP-PPA was helpful in reducing gastric damage induced by (+)-S-FP. However, hydrolysis of all rac-FP derivatives was found to be catalyzed by carboxylesterases in the gastric mucosa. The stereoselective disposition of FP enantiomers early after intravenous administration of rac-FP-PPA could be explained by the stereoselective formation of (-)-R-FP from rac-FP-PPA in the liver. (-)-R-FP-PPA was completely hydrolyzed to form (-)-R-FP in vivo, while 78% of (+)-S-FP-PPA was hydrolyzed to (+)-S-FP, with a corresponding decrease in the area under the curve. Twenty-five percent of (+)-S-FP-PPA might be eliminated as the intact prodrug or its metabolites other than FP. The most important bioconversion of FP-PPA occurred in plasma, and additional hydrolysis of the R-enantiomer in liver resulted in the stereoselectivity observed following both i.v. and p.o. administration. © 1996 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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