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  • 1
    Electronic Resource
    Electronic Resource
    Demethylation and cleavage of glycosidic bonds of 4‴-methyldigoxin in man (1972)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 272 (1972), S. 450-453 
    Details
    ISSN: 1432-1912
    Keywords: Urinary Excretion ; Methyldigoxin ; Digoxin ; Metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In man the oral or intravenous administration of 4‴-methyldigoxin yields metabolites in urine which are soluble either in chloroform or in water. The chromatographic analysis reveals demethylation as the main metabolic reaction in man. In addition to methyldigoxin and digoxin small amounts of digoxigenin-bisdigitoxoside and digoxigenin-mono-digitoxoside can be detected. The water soluble metabolites represent 7% of the radioactivity excreted in 7 days reaching a maximum within the first 8 h.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00501252
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  • 2
    Electronic Resource
    Electronic Resource
    Quantitative analysis of digoxin, 4‴-acetyldigoxin and 4‴-methyldigoxin and their metabolites in bile and urine of rats (1972)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 273 (1972), S. 154-167 
    Details
    ISSN: 1432-1912
    Keywords: Digoxin and Derivatives ; Bis- and Monodigitoxosides ; Biliary Excretion ; Renal Excretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The metabolism of digoxin (D), 4‴-acetyldigoxin (AD) and 4″-methyldigoxin (MD) was studied in biliary fistula rats by quantitative analysis of the excretion of these glycosides after intraduodenal administration. The total activity excreted within 12 h in bile amounts to 45.1; 40.5; 21.3 and in urine to 11.6; 14.3; 17.6% of the dose of D, AD and MD respectively. AD undergoes a rapid, but incomplete desacetylation in the organism. The highest desacetylation activities were found in liver, in intestinal mucosa and in kidney. Yet considerable amounts of unchanged AD were found in portal vein blood and still another 1–2% of the dose in bile and urine. In contrast MD is very slowly demethylated. 15 min after intraduodenal administration portal vein blood contains almost exclusively MD. A stepwise cleavage of digitoxoses from D as well as of AD and MD is indicated. The absolute amounts of digoxigenin-bis-digitoxoside (4–8% of the dose), digoxigenin-mono-digitoxoside (2.5–8.5%) excreted in bile and urine were in the same range for all three glycosides examined, although the relative amounts of these metabolites in bile and urine were much higher after administration of MD than of the two other glycosides. In addition a water-soluble fraction could be detected in bile and urine after administration of D, AD and MD. The absolute quantities of polar metabolites (4.5–7.0%) excreted in bile and urine were identical for all three glycosides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00508087
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  • 3
    Electronic Resource
    Electronic Resource
    Pharmacokinetic behaviour of 4‴-methyldigoxin in man (1972)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 273 (1972), S. 172-174 
    Details
    ISSN: 1432-1912
    Keywords: 4′-Methyldigoxin ; Half Life ; Excretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In 10 patients the time course of specific activity in plasma, and the excretion rates in urine and feces after oral and intravenous administration of 12α-3H-4‴-methyldigoxin were studied. The determined biological half life of radioactivity in plasma averaged 43 h and corresponds with the renal excretion velocity (50 h). 32.5 ± 5.0 and 31.5 ± 6.3% of the dose were found in feces and 59.7 ± 1.3 and 52.9 ± 1.8% were excreted in urine within 7 days after intravenous and oral administration, respectively. These results together with the observed plasma concentrations suggest a rapid and almost complete absorption of 4′-methyldigoxin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00508089
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  • 4
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of digoxin and its 4‴-acetyl-and methylderivates in the rat (1972)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 274 (1972), S. 171-181 
    Details
    ISSN: 1432-1912
    Keywords: Digoxin ; 4‴-Acetyldigoxin ; 4‴-Methyldigoxin ; Absorption Velocities ; Blood Level ; Biliar Excretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The kinetics of absorption, of changes in blood concentration, and of biliary excretion after the i.v. and i.d. administration of 40 μCi each, of digoxin, 4‴-acetyldigoxin and 4‴-methyldigoxin were studied in biliary fistula rats. The highest blood concentrations were found after the i.v. administration of 4‴-methyldigoxin, which decline with a half life time of 10 h, compared with 5.6 and 4.5 h for 4‴-acetyldigoxin and digoxin respectively. 71%, 55% and 17% of the dose were excreted in the bile within 12 h after the i.v. administration of digoxin, 4‴-acetyldigoxin and 4‴-methyldigoxin. The blood concentrations observed after the i.d. administration of digoxin and 4‴-acetyldigoxin show almost identical pharmacokinetics with respect to height and elimination velocity (half life 7.0 h for digoxin and 7.5 h for 4‴-acetyldigoxin). In contrast, following the i.d.administration of 4‴-methyldigoxin, blood concentrations, which were twice as high, were observed and declined with the same half life as after the i.v. administration. Determination of the disappearance rates of these glycosides from the intestinal lumen reveals a biphasic course of absorption. A first phase, with k values of 0.4, 0.5, 1.2 for digoxin, 4‴-acetyldigoxin and 4‴-methyldigoxin respectively is followed by a second phase with k values of 0.04, 0.04, 0.001 for digoxin, 4‴-acetyldigoxin and 4‴-methyldigoxin. Thus, 4‴-methyldigoxin is almost completely absorbed within the first two hours, while digoxin and 4‴-acetyldigoxin continue to be absorbed during the following hours. The absorption velocity of digoxin from the ileum was found to be one half of that seen in the duodenum. But this slow absorption, as well, follows a biphasic course. The data indicate that 4‴-methyldigoxin is absorbed at a distinctly higher rate than 4‴-acetyldigoxin and digoxin. Acetylation in 4‴ position evidently provides no important advantage with respect to absorption. While this study allows the determination of absorption and excretion velocities, no account of absorption quotes is given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00501851
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  • 5
    Electronic Resource
    Electronic Resource
    Evaluation of the enterohepatic circulation after 3H-digoxin administration in the rat (1972)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 275 (1972), S. 1-10 
    Details
    ISSN: 1432-1912
    Keywords: Enterohepatic Circulation ; Pharmacokinetics ; Digoxigenin-Bis- and Mono-Digitoxoside ; Polar Conjugates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After intraduodenal administration of 3H-digoxin (d) in biliary fistula (b.f.) rats, the total radioactivity in blood and bile is eliminated with t1/2 of 7 h in both fluids. In rats with intact enterohepatic circulation (e.c.), a t1/2 of 13.5 h was observed in blood and of 22 h in bile. To explain the much longer t1/2 in bile than in blood, the pharmacokinetics were studied of all substances, which might participate in e.c. after d administration. E.c. of the water soluble fraction is negligible since almost no absorption was found. Digoxigenin-bis- (b) and monodigitoxoside (m) showed approximately the same absorption kinetics as d. However, the blood levels of radioactivity after i.d. administration of these metabolites in b.f. rats were 5–6 times lower than those after d as a consequence of higher biliary excretion. 90–95% of the absorbed amounts of b and m were extrected in bile within 11 h compared with 61% after d administration. Thus the far longer t1/2 of elimination of radioactivity in bile than in blood after i.d. administration of d in rats with e.c. seemed to be due to a short circuit of b and m between intestine and liver. Evidence for this comes from the chromatographic analysis of the total radioactivity in the bile of these animals which shows that significantly more b is present in the bile of rats with e.c. than b.f. rats. No differences were found in the case of m, which on one hand is formed to a lesser extent and is on the other rapidly converted to polar metabolites, which are not reabsorbed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00505063
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  • 6
    Electronic Resource
    Electronic Resource
    Inelastic collision cross section of excited molecules (1971)
    Springer
    The European physical journal 243 (1971), S. 1-13 
    Details
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The (v′=6,J′=43) level in theB 1Π u electronic state of Na2 has been selectively populated by excitation with the 4 880 Å line of the argon laser. Through collisions with He atoms energy is transferred to neighbouring rotational states in Na2 and the density of these states is determined by observing fluorescence to electronic ground state. From previous measurement of the lifetime of theB 1Π u state and new measurements of the intensities of collision induced spectral lines as a function of He pressure, absolute collision cross sections for all rotational transitions up to ΔJ=±5 have been obtained. The total cross section for all rotational transitions observed is σ rot total =65±15 Å2. Preliminary results about collision induced vibrational transitions are also presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01401025
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  • 7
    Electronic Resource
    Electronic Resource
    NMR-Untersuchung der Molekularbeweglichkeiten teilkristalliner Polymerer (1973)
    Springer
    Colloid & polymer science 251 (1973), S. 962-979 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Summary The molecular motions of polymers change the line shapes of their NMR spectra. By analyzing the line shapes information is obtained about the type of motion and the number of the participating protons. Following a method firstly applied to polyethylene, the spectra of several partial crystalline polymers are decomposed into three components of differing line width. Hereby rigid, hindered mobile and microbrownian mobile protons can be distinguished. In the temperature range where all crystalline protons are rigid and all noncrystalline ones are mobile, the crystalline fraction of a polymer is identical with the rigid fraction. From this a new method for the determination of the crystallinity is derived. Furthermore in the case where all dielectric active motions are also NMR active, a correlation between NMR and dielectric properties is obtained such that a dielectric loss factor maximum always corresponds to a step of the mobile proton fraction. Finally it is found that only a small fraction of the noncrystalline protons is able to perform microbrownian motions. The following polymers are examined: polyethylene, polyoxymethylene, polyethylene oxide, polytetramethylene oxide, polyvinilidene chloride, polypropylene and 6 polyamide.
    Notes: Zusammenfassung Die Molekularbewegungen der Polymeren verändern die Linienform der NMR-Spektren. Aus der Linienformanalyse lassen sich Aussagen über die Art der Bewegung sowie die Zahl der daran beteiligten Protonen gewinnen. Nach einer zunächst an Polyäthylen erprobten Separationsmethode werden die Spektren einer Reihe teilkristalliner Polymerer in drei Komponenten unterschiedlicher Wendepunktsbreite zerlegt. Hierbei werden unbewegliche, behindert bewegliche und mikrobrownsch bewegliche Protonen unterschieden. In dem Temperaturbereich, in dem alle kristallinen Protonen unbeweglich und alle nichtkristallinen beweglich sind, stimmt die Kristallinität eines Polymeren mit dem unbeweglichen Protonenanteil überein. Hieraus leitet sich eine neue Methode der Kristallinitätsbestimmung ab. Ferner ergibt sich unter der fast immer erfüllten Voraussetzung, daß alle NMR-aktiven Bewegungen auch dielektrisch aktiv sind, eine Korrelation beider Meßverfahren derart, daß einem dielektrischen Verlustzahlmaximum stets eine Stufe des beweglichen Protonenanteils entspricht. Ein weiteres Ergebnis dieser Untersuchung ist, daß der Anteil der Protonen, die oberhalb der Glastemperatur zu einer mikrobrownschen Bewegung befähigt sind, in allen Fällen wesentlich kleiner als der nichtkristalline Anteil ist. Die Untersuchung erstreckt sich auf die Stoffe Polyäthylen, Polyoxymethylen, Polyäthylenoxid, Polytetramethylenoxid, Polyvinylidenchlorid, Polypropylen und 6-Polyamid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01498926
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  • 8
    Electronic Resource
    Electronic Resource
    Untersuchung des Härtungsablaufs ungesättigter Polyesterharze mit Hilfe von NMR-Messungen (1974)
    Springer
    Colloid & polymer science 252 (1974), S. 193-206 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Summary The restriction of molecular mobility of unsaturated polyester resins during the curing process is investigated by NMR measurements. By combining pulse and wide-line methods it is possible to study the whole curing process from the liquid resin to the cured material. Three kinds of protons can be distinguished: very mobile, less mobile and immobile ones, corresponding essentially to the unpolymerized styrene, the free polyester molecules and the already cured and glasslike regions, respectively. Both spin spin relaxation times of the liquid resins depend only on the viscosity of the solutions, but not on the structure of the resins. During the curing process a decrease of the larger relaxation time from approximately 0.3 to 2 · 10− 5 s and an increase of the rigid proton fraction is found. With the materials having a glass transition temperature above room temperature, still 7 to 18 percent of the protons are mobile after a curing at room temperature. By curing at increased temperature the mobile fraction drops to 3 to 7 percent. At the same time the mechanical strength of the sample increases. With the materials having a glass transition temperature below room temperature, however, the mobile fraction is much larger and there is no change with thermal treatment observed. The size of the mobile regions can be estimated from the fitting of the relaxation time and the mobile fractions at a fixed time of the curing. From light scattering and NMR measurements a new model for the structure of the cured materials is obtained. The model explains several properties of the cured material which cannot be explained by the model of an infinite network of the polyester molecules being connected by styrene bridges.
    Notes: Zusammenfassung Die Einschränkung der Molekularbeweglichkeit während der Härtung ungesättigter Polyesterharze wird durch NMR-Messungen verfolgt. Durch Kombination von Impuls- und Breitlinienmethode läßt sich der gesamte Härtungsablauf vom flüssigen Harz bis zum Formstoff untersuchen. Dabei werden drei Arten von Protonen unterschieden: stark bewegliche, die vornehmlich dem nicht einpolymerisierten Styrol zuzuschreiben sind, schwächer bewegliche, die im wesentlichen den unvernetzten Polyestermolekülen entsprechen und unbewegliche, die den bereits vernetzten und glasartig erstarrten Bereichen angehören.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01638100
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  • 9
    Electronic Resource
    Electronic Resource
    NMR-Untersuchung des Relaxationsverhaltens von Polyäthylen (1972)
    Springer
    Colloid & polymer science 250 (1972), S. 1094-1104 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Summary The relaxation behavior of polyethylene is studied by analyzing the line shape of the NMR-spectra. The broad, medium and narrow components correspond to three kinds of molecular motion: rigid, hindered mobile and liquid like mobile. The line shapes of the components are assumed to be that of a completely crystalline polyethylene sample, a hybrid between aGauβ andLorentz curve, and aLorentz curve, respectively. For a melt crystallized linear polyethylene of density 0,972 gcm−3 it is found that only (25±3)% of the noncrystalline protons are able to participate in the liquid like motion. For solution crystallized polyethylene this fraction is only (3±1)%. By swelling the polyethylene with carbon tetrachloride the mobility of the noncrystalline regions is increased. This is seen by the lowering of the glass transition temperature and a narrowing of the medium and narrow component. Branched polyethylene shows a different relaxation behavior from linear polyethylene, which follows from the disturbance of the polyethylene structure by the branching points.
    Notes: Zusammenfassung Die Untersuchung des Relaxationsverhaltens von Polyäthylen geschieht durch die Linienformanalyse der NMR-Spektren. Der breiten, mittleren und schmalen Komponente entsprechen drei Arten der Molekularbeweglichkeit: unbeweglich, behindert beweglich und fiüssigkeitsähnlich beweglich. Zur mathematischen Beschreibung der breiten Komponente benutzen wir die an einer hochkristallinen Probe experimentell bestimmte Kurvenform, für die mittlere Komponente eine ausGauss- undLorentz-Kurve gemischte Kurve und für die schmale Komponente eineLorentz-Kurve. Die Wendepunktsbreiten der drei Komponenten betragen 14 bis 16 G, 2 bis 10 G und⩽1G. Es wird gefunden, daß bei schmelzkristallisiertem linearem Polyäthylen der Dichte 0,972 g cm−3 nur (25±3)% aller nichtkristallinen Protonen eine flüssigkeitsähnliche Bewegung ausführen. Bei lösungskristallisiertem linearem Polyäthylen derselben Kristallinität ist der Anteil mit (3 ±1)% noch wesentlich kleiner. Durch die Quellung des Polyäthylens mit Tetrachlorkohlenstoff erhöht sich die Beweglichkeit in den nichtkristallinen Bereichen. Dies äußert sich in der Erniedrigung der Glastemperatur sowie in einer Verschmälerung der mittleren und schmalen Komponente. Verzweigtes Polyäthylen zeigt aufgrund seiner durch die Verzweigungsstellen gestörten Struktur ein von linearem Polyäthylen abweichendes Verhalten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01498892
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  • 10
    Electronic Resource
    Electronic Resource
    Zur Kenntnis der Verbindungen des zwei- und dreiwertigen Vanadins. I. Über die Ammoniakate des Vanadin(III)-chlorids (1950)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 262 (1950), S. 223-228 
    Details
    ISSN: 0372-7874
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1.Es wurde das Verhalten von VCl3 gegen NH3 untersucht. Dabei fanden sich Ammoniakate mit 12, 7, 6, 5, 3 und 2 NH3. Die Bildungswärmen wurden berechnet.2.Die Ergebnisse sind bei Temperaturen oberhalb Zimmertemperatur mit Beobachtungen von EPHRAIM und AMMANN im Einklang; dagegen konnten die Angaben von J. MEYER und BACKA über die Entstehung von Vanadinnitrid bei der Einwirkung von NH3-Gas auf VCl3 nicht bestätigt werden.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19502620128
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