ISSN:
1432-1041
Keywords:
Methyldigoxin
;
excretion
;
deep compartment
;
O-demethylation
;
glycosides
;
metabolism
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Medicine
Notes:
Summary The time course of radioactivity in plasma and the excretion in urine and faeces over 7 days were determined in 12 healthy subjects after single oral and intravenous doses of a solution of3H-β-methyldigoxin. 62.2±2.1 and 29.0±5.2 per cent of the dose were excreted in urine and faeces, respectively, within 7 days of intravenous administration, compared with 55.2±2.8 and 28.6±5.7 per cent after oral administration. This indicates almost complete absorption of the glycoside when given in solution. 12 hours after its administration a pseudo-distribution equilibrium was reached and the average half life of tritiated compounds was 1.3 days. By 48 – 96 hours after treatment the average half life was 2.8 days. O-demethylation was revealed as the main metabolic degradation step in man. The rate of Demethylation was higher after oral than i.v. administration. Thus, only 31% of the radioactivity excreted in the urine consisted of unchanged β-methyldigoxin after oral administration compared to 51% after i.v. dosing. Only traces of bis- and monoglycosides were excreted in urine, but there were considerable amounts in faeces, where they accounted for more than 35% of the total excretion. Up to 40% of the radioactivity in plasma and urine consisted of polar conjugates during the first 12 hours after administration of β-methyldigoxin. The mono- and bisglycosides were identified as the main products of conjugation. During the 7 days approximately 15% of the administered dose was metabolized by splitting off glycosidic bonds and conjugation to polar compounds.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00614005
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