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  • 1990-1994  (14)
  • 1980-1984  (11)
  • 1970-1974  (5)
  • 1965-1969  (3)
  • 1950-1954  (1)
  • 1925-1929  (3)
  • 1915-1919  (1)
  • 1890-1899  (4)
  • Chemistry  (41)
  • polyvinylpyrrolidone
  • 1
    Electronic Resource
    Electronic Resource
    Biopharmaceutical and physicochemicai studies on reserpine-polyvinylpyrrolidone coprecipitates (1974)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 2 (1974), S. 511-524 
    Details
    ISSN: 1573-8744
    Keywords: absorption ; reserpine ; bioavailability ; coprecipitates ; polyvinylpyrrolidone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The effect of varying the composition of drug- polyvinylpyrrolidone coprecipitates on the oral absorption characteristics of reserpine was assessed in the rat by urinary excretion studies. Both the rate and extent of absorption of reserpine from either a 1∶2,1∶5,or 1∶10 (w/w)ratio reserpinepolyvinylpyrrolidone coprecipitate were increased two- to threefold. This finding indicates that at coprecipitate ratios of 0.5or less, the enhanced absorption of reserpine is apparently independent of polyvinylpyrrolidone content. The in vitrodissolution rates of these test systems at 37°Ccorrelated very well with the in vivoabsorption data, suggesting dissolution rate- limited absorption, The results of physicochemical studies suggest that on coprecipitation of reserpine with polyvinylpyrrolidone a highly energetic form of the drug, most probably amorphous in nature, is formed. The solubility characteristics of this high- energy crystal form, as compared to those of the most thermodynamically stable form of the drug, appear to be responsible for the marked enhancement noted in both the dissolution and the absorption of reserpine from polyvinylpyrrolidone coprecipitates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01070945
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  • 2
    Electronic Resource
    Electronic Resource
    Macromolecules in solution, Hertbert Morawetz, Interscience, New York, 1965. 495 pp. + xvi, $16.50 (1966)
    New York : Wiley-Blackwell
    Biopolymers 4 (1966), S. 1053-1053 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1966.360040912
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  • 3
    Electronic Resource
    Electronic Resource
    Viscoelastic and rheological properties of concentrated solutions of proteoglycan subunit and proteoglycan aggregate (1990)
    New York : Wiley-Blackwell
    Biopolymers 29 (1990), S. 1587-1592 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oscillatory and steady shear rheological properties of concentrated solutions of proteoglycan subunit (PGS) and aggregate (PGA) from bovine articular cartilage have been studied using a Rheometrics fluids spectrometer. At comparable concentrations in the physiological range tan δ increases from 0.5 to 1.0 for PGA as the oscillation frequency (ω) increases from 10-1 to 102 rads / s, compared to a decrease from 40 to 5 for PGS. Thus PGA solutions exhibit predominantly elastic response whereas those of PGS exhibit primarily viscous behavior. PGA solutions show pronounced shear-thinning behavior at all shear rates (γ) in the range 10-2 〈 γ (s-1) 〈 10 2, whereas PGS solutions exhibit predominantly Newtonian flow. For PGA, the small-strain complex viscosity η* (ω) is substantially smaller than the steady-flow viscosity η (γ) at comparable values of ω and γ. These observations indicate that the presence of proteoglycan aggregates leads to formation of a transient or weak-gel network. Since aggregation leads to a large increase in molecular hydrodynamic volume and hence in the relaxation times for macromolecular rotation, it appears that role of aggregate formation is to shift the linear viscoelastic response from the terminal viscous flow into the plateau elastomeric regime of relaxational behavior. Normal or pathological changes that produce a decrease in aggregation will result in a loss of elastomeric behavior of the proteoglycan matrix.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360291208
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  • 4
    Electronic Resource
    Electronic Resource
    The thermodynamics of hydrogen isotope exchange in lysozyme: The influence of glycerol (1990)
    New York : Wiley-Blackwell
    Biopolymers 29 (1990), S. 1175-1183 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The temperature dependence of hydrogen isotope exchange rates for lysozyme in 5 molal aqueous glycerol and for poly (D,L-alanine) in a range of glycerol concentrations from 0 molal to 8 molal have been determined. The activation enthalpy of base-catalyzed exchange for poly (D,L-alanine) in water is 4 kcal/mol and passes through a minimum at about 2 molal glycerol before returning to a value of 4 kcal/mol at 4 molal glycerol. Exchange rates for lysozyme have been analyzed with transition state and Kramers's theories. The activation parameters for exchange of protons in lysozyme in the presence of 5 molal glycerol show a similar qualitative behavior to those determined for exchange in the absence of glycerol [R. B. Gregory et al. (1982) Biochemistry 24, 6523-6530]. The activation enthalpies and entropies for the fast-exchanging protons show a gentle increase as H(t), the number of hydrogens remaining unexchanged, decreases. By contrast, the activation parameters for the slowest exchanging protons [H(t) 〈 20] increase dramatically as H(t) decreases. As in water, the activation parameters for exchange of the fast- and slow-exchanging protons in glycerol solution are characterized by two distinct compensation temperatures (510 ± 100 K for the fast protons and 340 ± 40K for the slow protons). These values are not significantly different from those determined for exchange in water.The activation parameters, ΔH
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360290808
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  • 5
    Electronic Resource
    Electronic Resource
    Mikrobiologische Umwandlungen nichtsteroider Strukturen, V. Mikrobiologische Reaktionen von substituierten 1-Äthyl-4-oxo-1,4-dihydrochinolin-3-carbonsäuren (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 2636-2642 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Microbiological Transformations of Nonsteroidal Structures, V. Microbiological Reactions of Substituted 1-Ethyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acids1-Ethyl-7-methyl-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (1) is transformed to the methyl ester by Streptomyces surinam. Penicillium adametzi hydroxylates the substrate at the 7-methyl substituent, whereas 1 -ethyl-8-methoxy-5-methyl-4-oxo- 1,4-dihydroquinoline-3-carboxylic acid (4) is hydrolyzed to the free phenol by the same fungi. l-Ethyl-4-oxo-1,4,6,7,8,9-hexahydrobenzo[g]quinolinc-3-carboxylic acid (6) is hydroxylated in 7 - and 8-position by Penicillium adametzi, in 6- and 7- (or 8-) position by Streptomyces achromogenes and in 6-position by Sporotrichum sulfurescens. 5-Ethyl-8-oxo-2,3,5,8-tetrahydrofuro[2,3-g]quinoline-7-carboxylic acid (10) undergoes only a hydrolytic cleavage of the dihydrofuranering.
    Notes: 1-Äthyl-7-methyl-4-oxo-1,4-dihydrochinolin-3-carbonsäure (1) wird durch Streptomyces surinam in den Methylester umgewandelt. Penicillium adametzi hydroxyliert das Substrat am 7-Methylsubstituenten, während bei der 1 -Äthyl-8-methoxy-5-methyl-4-oxo- 1, 4-dihydrochinolin-3-carbonsäure (4) mit dem gleichen Pilz nur eine Phenolätherspaltung eintritt. 1-Äthyl-4-oxo-l,4,6,7,8,9-hexahydrobenzo[g]chinolin-3-carbonsäure (6) wird von Penicillium adametzi in 7- und 8-, von Streptomyces achromogenes in 7-(oder 8-) und 6- sowie von Spororrichum sulfurescens in 6-Stellung hydroxyliert. 5-Äthyl-8-oxo-2,3,5,8-tetrahydrofuro[2,3-g]-chinolin-7-carbonsäure (10) zeigt nur eine hydrolytische Spaltung des Dihydrofuranringes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731060827
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  • 6
    Electronic Resource
    Electronic Resource
    Recherches sur les silicates (1928)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 11 (1928), S. 731-750 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: L'étude de la conductibilité des silicates aux températures élevées peut servir à déceler et à suivre des réactions dont ces silicates peuvent être le siège.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19280110185
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  • 7
    Electronic Resource
    Electronic Resource
    Mikrobiologische Umwandlungen nichtsteroider Strukturen, III.I. und II. Mitteil.: H. Kosmol, K. Kieslich und H. Gihian, Liebigs Ann. Chem. 711, 38 bzw. 42 (1968). Hydroxylierung von 5-Alkyl-2-(benzolsulfonylamino)pyrimidinen und strukturverwandten Antidiabetika (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 1290-1302 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Microbiological Transformations of Nonsteroidal Structures, III. Hydroxylation of 5-Alkyl-2-(benzenesulfonylamino)pyrimidines and Structurally Related Antidiabetics5-Alkyl-2-(arylsulfonylamino)pyrimidines (1-5 and 11-16) have been hydroxylated microbiologically Propyl, butyl, and isobutyl groups were hydroxylated at C-2, ethyl groups at C-1, isopropyl groups at C-1 and C-2, and neopentyl groups at C-3, respectively, by Streptomyces griseolus. The sulfonylurea part of the antidiabetics glibenclamid (25) and glisoxepid (29) was degradated to sulfonamide; in addition, hydroxyl groups were introduced into the 2- and 4-positions of the cyclohexane ring of 25.
    Notes: 5-Alkyl-2-(arylsulfonylamino)pyrimidine (1-5 und 11-16) wurden mikrobiologisch hydroxyliert. Mit Streptomyces griseolus wurden Propyl-, Butyl- und lsobutylgruppen an C-2, äthylgruppen an C-1, Isopropylgruppen an C-1 und C-2, sowie Neopentylgruppen an C-3 hydroxyliert. Die Antidiabetika Glibenclamid (25) und Glisoxepid (29) mit Sulfonylharnstoff-Struktur wurden zu Sulfonamiden abgebaut, ferner wurden in 2- und 4-Stellung des Cyclohexanrings von 25 Hydroxylgruppen eingeführt.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731060426
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  • 8
    Electronic Resource
    Electronic Resource
    Über die Oxydationsgeschwindigkeit von Bromwasserstoff mittels Chromsäure in Gegenwart von Salzen (1929)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 177 (1929), S. 137-144 
    Details
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19291770116
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  • 9
    Electronic Resource
    Electronic Resource
    Über die Oxydationsgeschwindigkeit von Bromwasserstoff mittels Chromsäure in Gegenwart von Chloriden und die katalytische Beeinflussung der Mn″-Ionen im Salzmilieu (1929)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 182 (1929), S. 74-92 
    Details
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Während die Brom-Austreibung in Gegenwart von Sulfaten in allen Konzentrationen des betreffenden Salzes, je nach dem an- gewandten Sulfat, entweder beschleunigt oder verzögert wird, wirken alle Chloride niederer Konzentration ausschließlich verzögernd. Überall hat man ein Maximum der Verzögerung im Gebiet von etwa n/1-Endkonzentration. Es ergibt sich folgende Reihe ab- nehmender Verzögerung: \documentclass{article}\pagestyle{empty}\begin{document}$$ Me^I Cl 〉 Me^{II} Cl_2 \ge Me^{III} Cl_3. $$\end{document}Eine spezifische Kationenwirkung ist nicht feststellbar. HCl ver- hält sich genau wie ein neutrales Chlorid. Das H-Ion liegt in seiner Wirkung zwischen den ein- und mehrwertigen Kationen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19291820107
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  • 10
    Electronic Resource
    Electronic Resource
    Uranium binding by emulsan and emulsanosols (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 25 (1983), S. 1725-1735 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Emulsan, the extracellular bioemulsifier of Acinetobacter RAG-1, bound up to 0.9 μm of uranium per 1 mg emulsan. The dissociation constant for the emulsan-uranium complex, KappI was 1.2 × 10-4M. Much larger amounts of uranium were bound to emulsan when the biopolymer occurred on hexadecane-water interfaces. Under these conditions, more than 3.5 µm uranium were bound per 1 mg emulsan and the dissociation constant KappII was 5.1 × 10-5M. At pH 2, more than 90% of the uranium bound to emulsan on the hexadecane-water interface was desorbed, while less than 10% bioemulsifier was released from the interface. The different binding parameters of emulsan when free in solution and while adsorbed onto the hexadecane water interface are discussed in view of potential applications and as a model system for studying the properties of an extracellular amphipathic polymer bound to a hydrophobic surface.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260250704
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