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  • 1
    Electronic Resource
    Electronic Resource
    Conjugation of copper-zinc superoxide dismutase with succinylated gelatin: Pharmacological activity and cell-lubricating function (1993)
    s.l. : American Chemical Society
    Bioconjugate chemistry 4 (1993), S. 490-498 
    Details
    ISSN: 1520-4812
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/bc00024a011
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  • 2
    Electronic Resource
    Electronic Resource
    Comparative study on inclusion complexations of antiinflammatory drug flurbiprofen with β-cyclodextrin and methylated β-cyclodextrins (1984)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 2 (1984), S. 597-604 
    Details
    ISSN: 1573-1111
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstruct Some physicochemical properties of methylated β-cyclodextrins, i.e., heptakis(2,6-di-O-methyl)-β-cyclodextrin (DM-β-CyD) and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TM-β-CyD) were compared with those of natural β-cyclodextrin (β-CyD). Inclusion behaviors of β-CyD and methylated β-CyDs in water and in solid state were studied by solubility analysis, spectroscopies (UV, CD,13C-NMR and IR), X-ray diffractometry and thermal analysis, using an antiinflammatory drug flurbiprofen (FP) as a guest molecule. The spectral data suggest that the inclusion mode of FP-TM-β-CyD is somewhat different from those of FP-β-CyD and FP-DM-β-CyD. The solid complexes of FP with β- and methylated β-CyDs were obtained in molar ratio of 1∶1, and their dissolution behavior and release from suppository base were examined. The data are presented suggesting that DM-β-CyD is particularly useful for improving the pharmaceutical properties of FP in various dosage forms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00662225
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  • 3
    Electronic Resource
    Electronic Resource
    The Controlled Release of Prednisolone Using Alginate Gel (1994)
    Springer
    Pharmaceutical research 11 (1994), S. 272-277 
    Details
    ISSN: 1573-904X
    Keywords: alginate ; gel beads ; controlled release ; prednisolone ; in vitro/in vivo correlation ; beagle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In a release study of alginate gel beads, swelling and erosion of the beads were observed at pH 6.8, whereas no swelling occurred at pH 1.2. The amount of released prednisolone (PL) was greater at pH 6.8 than at pH 1.2. The lower the ratio of mannuronic acid block to guluronic acid block in alginate, the slower the release of PL. An increase in loaded PL in the beads resulted in a slower release of PL. The decrease in bead size caused a rapid release of PL. The addition of sodium alginate propylene glycol ester elevated the extent of PL release. The plasma profile of PL showed sustained-release behavior after the oral administration of the beads to beagles. Furthermore, the correlation between in vitro release and in vivo absorption of PL for various alginate gel beads was evaluated using deconvolution and convolution methods. The in vivo absorption of PL was correlated with the PL release at pH 1.2, and it differed from that at pH 6.8. The release of PL from alginate gel beads in vivo appeared to occur under conditions that cause little swelling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018963626248
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  • 4
    Electronic Resource
    Electronic Resource
    Evaluation of Stereoselective Transdermal Transport and Concurrent Cutaneous Hydrolysis of Several Ester Prodrugs of Propranolol: Mechanism of Stereoselective Permeation (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 1524-1529 
    Details
    ISSN: 1573-904X
    Keywords: prodrug ; penetration ; stereoselectivity ; hydrolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The purpose of this study was to evaluate the stereoselective permeation and concurrent cutaneous hydrolysis of a series of ester prodrugs of propranolol (PL). Methods. In vitro studies were performed across full-thickness, stripped and diisopropylfluorophosphate (DFP) treated skins of hairless mouse with flow-through diffusion cells at 37°C. Results. The permeability coefficients (K p), which were dependent on partition coefficients (PC), of all the prodrugs were markedly increased compared to the parent drug. In full-thickness skin, the (R) caproyl-PL (CR-PL) showed the highest K p, which was about 52-fold greater than that of PL. Most of the more lipophilic prodrugs showed stereoselectivity in K p (R 〉 S). All the prodrugs underwent stereoselective hydrolysis (R 〉 S) during penetration. The prodrugs which showed stereoselectivity in permeation were comparatively lipophilic and showed great differences in hydrolysis percentages between the enantiomers. Permeation studies with stripped skin revealed that prodrugs were more permeable across stratum corneum compared to PL, whereas reverse was happened across viable skin. Although CR-PL showed high stereoselectivity in permeation across full-thickness skin and underwent higher percent of concurrent stereoselective cutaneous hydrolysis, the prodrug showed no stereoselectivity in permeation across DFP, an esterase inhibitor, treated skin and the concurrent cutaneous hydrolysis was also stopped. Conclusions. Lipophilic prodrugs may readily pass the stratum corneum but may not be able to penetrate so easily through the deeper tissues. Unlike the (S) isomers, the (R) isomers of lipophilic prodrugs almost completely converted to propranolol in epidermis and can easily pass through the dermis layer, resulting in stereoselective penetration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016031629845
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  • 5
    Electronic Resource
    Electronic Resource
    Species Differences in Stereoselective Hydrolase Activity in Intestinal Mucosa (1998)
    Springer
    Pharmaceutical research 15 (1998), S. 626-631 
    Details
    ISSN: 1573-904X
    Keywords: O-acyl-propranolol ; stereoselective hydrolysis ; intestinal mucosa ; carboxylesterase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The aim of this study is to investigate species differences in the stereoselective hydrolysis for propranolol ester prodrugs in mammalian intestinal mucosa and Caco-2 cells. Methods. Hydrolase activities for propranolol prodrugs and p-nitro-phenylacetate in man (age: 51−71 years), the beagle dog (age: 4 years) and Wistar rat (age: 8 weeks) intestinal mucosa, and also in Caco-2 cells (passage between 60−70) were estimated by determining the rate of production of propranolol and p-nitrophenol, respectively. Results. The hydrolase activities for both propranolol prodrugs and p-nitrophenylacetate were in the order of man 〉 rat 〉〉 Caco-2 cells 〉 dog for intestinal microsomes, and rat 〉 Caco-2 cells = man 〉 dog for intestinal cytosol. Dog microsomes showed stereoselective hydrolysis for propranolol prodrugs, but not those from human or rat. Interestingly, both subcellular fractions of Caco-2 cells showed remarkable R-enantioselectivity except acetyl propranolol. Enzyme kinetic experiments for each enantiomer of butyryl propranolol in microsomes revealed that dog possesses both low and high affinity hydrolases. Both Km and Vmax values in rat were largest among examined microsomes, while Vmax/Km was largest in man. Finally, it was shown that the carboxylesterases might contribute to the hydrolysis of propranolol prodrug in all species by inhibition experiments. Conclusions. The hydrolase activities for propranolol prodrugs and p-nitrophenylacetate in intestinal mucosa showed great species differences and those in human intestine were closer to those of rat intestine than dog intestine or Caco-2 cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011946314416
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  • 6
    Electronic Resource
    Electronic Resource
    In Vitro and In Vivo Evaluation of the Enhancing Activity of Glycyrrhizin on the Intestinal Absorption of Drugs (1999)
    Springer
    Pharmaceutical research 16 (1999), S. 80-86 
    Details
    ISSN: 1573-904X
    Keywords: dipotassium glycyrrhizinate ; glycyrrhetinylmonoglucuronide ; glycyrrhetinic acid ; salmon calcitonin ; absorption enhancer ; β-glucuronidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. The enhancing activity of dipotassium glycyrrhizinate (Grz) on the intestinal absorption of drugs has been demonstrated in an in vitro study using Caco-2 cell monolayers and in an in vivo absorption study in rats. Methods. The hydrolysis of Grz by luminal content and mucosa of the rat colon was investigated. The absorption-enhancing activity of Grz and its hydrolysates was estimated by changes in transepithelial electrical resistance (TEER) and the permeation of sodium fluorescein (Flu-Na) in Caco-2 cell monolayers. It was further evaluated through the absorption of salmon calcitonin (sCT) in the rat colon. Results. Grz was not hydrolyzed to glycyrrhetinylmonoglucuronide (GrMG) and glycyrrhetinic acid (GA) by colonic mucosa, but, rather by the β-glucuronidase in colonic flora. The hydrolysis of Grz to GrMG was extremely slow and the GrMG produced was rapidly regenerated to GA. Grz and GrMG had no effect on TEER nor on the permeability of Flu-Na across Caco-2 cell monolayers. On the other hand, GA decreased TEER and increased the permeability of Flu-Na in a dose-dependent manner. However, Grz and GrMG enhanced the plasma calcium-lowering effect of sCT after administration in the rat colon. The coadministration of sCT and GA in the rat colon induced the strongest plasma calcium-lowering effect and the highest plasma concentration of sCT. Conclusions. The in vivo enhancing-activity of Grz in the absorption of drugs is dependent on GA, a hydrolysis product of Grz resulting from the action of β-glucuronidase in intestinal flora.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018822829302
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  • 7
    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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  • 8
    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.
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  • 9
    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.
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  • 10
    Electronic Resource
    Electronic Resource
    Drug Binding to α1-Acid Glycoprotein Studied by Circular Dichroism (1989)
    Springer
    Pharmaceutical research 6 (1989), S. 156-159 
    Details
    ISSN: 1573-904X
    Keywords: circular dichroism ; α1-acid glycoprotein ; binding force ; binding site ; protein binding of drugs ; α1-acid glycoprotein binding of acidic and basic drugs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The interactions of acidic and basic drugs with α1-acid glycoprotein (α1-AGP) were investigated using circular dichroism (CD) measurements. Extrinsic Cotton effects were generated by the binding of drugs to α1-AGP. The CD data suggested the presence of a single binding site on the α1-AGP molecule. The induced ellipticities of the acidic drug–α1-AGP system decreased with increasing pH, while the ellipticities for the basic drugs increased with pH. The ellipticities for all drugs were reduced by the addition of fatty acids. Furthermore, the induced ellipticities decreased in the presence of cesium chloride for basic drugs bound to α1-AGP. The extrinsic Cotton effects therefore appear to result from hydrophobic interaction with α1-AGP for the acidic drugs and from hydrophobic and electrostatic interactions for the basic drugs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1015936710919
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