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  • 1970-1974  (3)
  • Brain  (1)
  • Cardiac Output  (1)
  • Glibenclamide  (1)
  • 1
    Electronic Resource
    Electronic Resource
    β-Methyl-digoxin (1973)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 279 (1973), S. 211-226 
    Details
    ISSN: 1432-1912
    Keywords: Cardiac Glycosides ; Brain ; Behaviour ; Distribution ; Protein Binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Rats and mice were injected with 3H-labelled β-methyldigoxin, digoxin or digitoxin i.p. Four hours later, the concentrations of radioactivity were measured in the plasma and in skeletal muscle or in the brain. Protein binding in the plasma was determined and the concentration of radioactivity in the plasma water was calculated. By dividing the injected dose or the concentration in the tissue by that in the plasma water, distribution coefficients (DCs) were calculated for the whole body, skeletal muscle and brain. Some extra-cardiac effects of the three glycosides were quantified and the concentrations that may be expected in plasma water, skeletal muscle and brain after the administration of equiactive doses were calculated. 1. The DC of the injected dose was lower for β-methyl-digoxin than for digoxin and digitoxin. This difference cannot be explained by a slow elimination of β-methyl-digoxin suggesting that it has a low distribution volume in these species. 2. In rats, the DC between skeletal muscle and plasma water decreased in the order digitoxin 〉 digoxin ≫ β-methyl-digoxin. 3. In mice and rats, the DC between brain and plasma water decreased in the order digitoxin ≫ β-methyl-digoxin 〉 digoxin. 4. Protein binding decreased in the order digitoxin ≫ digoxin 〉 β-methyldigoxin. 5. In rats, the doses producing an equal increase in potassium excretion decreased in the order digitoxin 〉 digoxin 〉 β-methyl-digoxin. On the other hand, the concentrations of radioactivity in the plasma water correlated with these doses decreased in the order β-methyl-digoxin 〉 digitoxin ≫ digoxin. There was no significant difference between the intracellular concentrations of digoxin and β-methyl-digoxin in skeletal muscle. 6. In mice, there was no clear correlation between inhibition of spontaneous motility or righting reflexes on the rotating rod and the concentrations of radioactivity in the plasma water or in the brain. β-Methyl-digoxin is moee lipophilic than digoxin but it penetrates less into skeletal muscle. It is as lipophilic as digitoxin, but it penetrates less into the brain of rats and mice. This shows that penetration of the cell membrane by cardiac glycosides does not solely depend on lipid solubility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00500601
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    β-Methyl-digoxin (1972)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 272 (1972), S. 32-45 
    Details
    ISSN: 1432-1912
    Keywords: Cardioglycoside ; Labelled Compound ; Absorption ; Cardiac Output ; Guinea-Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Glycosides were injected into a ligated loop of the small intestine of guinea-pigs under urethane anaesthesia. From the residual radioactivity in the intestinal loop at various times after the injection the amount absorbed was determined and from that the rate of absorption, assuming exponential absorption. β-Methyl-digoxin was absorbed more rapidly than digoxin and its derivatives β-acetyl-digoxin and lanatoside C but slower than digitoxin. β-Methyl-digoxin was much better absorbed from a suspension than from a solution; this caused the difference from digitoxin to disappear to a large extent. The high rate of absorption of β-methyl-digoxin in humans is probably explicable in this way. The rate of absorption of β-methyl-digoxin was independent of the dose until the appearance of arrhythmias; it decreased with progressing intoxication. Absorption was delayed when cardiac output was decreased by barbital anaesthesia. The amount absorbed at the onset of arrhythmias can be calculated from the injected dose, the rate of absorption and the time. For β-methyl-digoxin and digoxin it corresponded to the effective doses determined by intravenous infusion and to the cardiotoxicity after intraduodenal injection. The cardiotoxicity of β-acetyl-digoxin and digitoxin was less than that expected from the amounts absorbed suggesting metabolic inactivation during absorption. The relative enteral activity is not only determined by the absorption but also by the rate of elimination. The rate at which the material should leave the intestine in order to maintain arrhythmia was calculated. It was considerably greater for digitoxin than for β-methyl-digoxin or digoxin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00498792
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Ursachen der Potenzierung der hypoglykämischen Wirkung von Sulfonylharnstoff-Derivaten durch Medikamente (1971)
    Springer
    European journal of clinical pharmacology 4 (1971), S. 32-37 
    Details
    ISSN: 1432-1041
    Keywords: Glibenclamide ; pharmacokinetics ; metabolism ; potentiation of hypoglycemic action ; phenylbutazone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Description / Table of Contents: Summary Metabolically healthy subjects were given an intravenous injection of 1,13 mg14C-labelled glibenclamide (HB 419). The plasma level, renal elimination of the radioactivity and metabolism of the substance were investigated. Two minutes after administration the HB 419 is virtually present only in the blood and at the end of the distribution period mostly in the extracellular space. 53% of the radioactivity is excreted via the kidneys in the form of metabolites. If glibenclamide is administrated in the same way to the same subjects after pretreatment with phenylbutazone there are no differences in the course of the plasma levels or the rate of elimination from the blood. There is, however, a significant difference in the excretion of the radioactivity in the urine. In the presence of phenylbutazone significantly less HB 419 metabolite is excreted renally. In view of the known alternative route of elimination it is suggested that the amount not excreted in the urine is in compensation eliminated via the bile. There was no difference in the metabolism of glibenclamide between the control and phenylbutazone treated groups. The potentiation by phenylbutazone of HB 419 action, and probably also that of other antidiabetic sulphonylureas, must therefore be due predominantly to other causes (Communication III).
    Notes: Zusammenfassung Stoffwechselgesunde Versuchspersonen erhielten14C-markiertes Glibenclamid in einer Dosis von 1.13 mg/Vpn i.v. gespritzt. Plasmaspiegelverläufe, renale Elimination der Radioaktivität und die Metabolisierung der Substanz wurden untersucht. Zwei Minuten nach der Applikation ist HB 419 praktisch nur im Blutund nach Abschluß der Verteilung weitgehend im Extracellulärraum vorhanden. 53% der Radioaktivität werden über die Nieren in Form von Metaboliten ausgeschieden. Wird den gleichen Probanden nach Prämedikation mit Phenylbutazon Glibenclamid in gleicher Weise verabfolgt, ergibt sich kein Unterschied hinsichtlich der Plasmaspiegelverläufe und der Eliminationsgeschwindigkeit aus dem Blut. Ein signifikanter Unterschied besteht jedoch in der Ausscheidung der Radioaktivität in den Harn (26.3%). In Gegenwart von Phenylbutazon wird ein signifikant geringerer Anteil von HB 419-Metaboliten renal eliminiert. Aufgrund des bekannten zweiten Ausscheidungsweges wird vermutet, daß der fehlende Anteil kompensatorisch über die Galle eliminiert wird. Die Metabolisierung von Glibenclamid weist keine Differenzen zwischen Phenylbutazon-und Kontroll-Gruppe auf. Die Wirkungspotenzierung von HB 419 — wahrscheinlich auch diejenige anderer antidiabetisch wirksamer Sulfonylharnstoffe — durch Phenylbutazon dürfte demnach überweigend andere Ursachen haben. (Mitteilung III).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00568896
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    Paper (German National Licenses)
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