Cardiac Activity of Newer Digitalis Glycosides and Aglycones

Henderson, Francis G.; Chen, K. K.

doi:10.1021/jm01240a011

Cited by 17 publications

(1 citation statement)

References 23 publications

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“…In cats, Bottcher, Lullrnann & Proppe (1973), using a heart-lung preparation, found that at 50% of peak inotropic effect, the relative potency of the bis-and mono-digitoxosides of digoxigenin were 1.26 and 1.44, compared with digoxin taken as unity. Marcus & others (1979, recalculated the data of Henderson & Chen (1962) and Chen (1 970) obtained in cats. On the basis of pmol mg-l body weight, the relative toxicities, compared with digoxin as unity, were digoxigenin-bis-digitoxoside 1.0, digoxigenin-mono-digitoxoside 1.4 and digoxigenin 0.3.…”

Section: Discussionmentioning

confidence: 99%

Hydrolysis of digoxin by acid

Gault

Charles

Sugden

et al. 1977

Journal of Pharmacy and Pharmacology

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Predictable hydrolysis of [3H]digoxin-12alpha occurred in vitro with incubation in HCl or gastric juice. Hydrolysis varied with pH, time, temperature and agitation. Digoxin, the bis- and mono-digitoxosides of digoxigenin and digoxigenin were separated by silica gel thin-layer chromatography using chloroform-ethyl acetate-glacial acetic acid (25:25:1 v/v) and were quantitated by liquid scintillation spectrometry. Hydrolysis with incubation at 37 degrees and pH 3 for 90 min was minimal, but increased with increasing acidity until greater than 70% was hydrolysed at pH 1-2 after 30 min and greater than 96% after 90 min incubation. At pH 0-9, 87% was hydrolysed after 30 min. In vitro hydrolysis in gastric fluid was slightly less than in HCl at the same pH. A volunteer was given 150 muCi[3H]digoxin-12alpha by nasogastric tube during a pentagastrin infusion when gastric pH was 0-94. He remained on his left side and samples were aspirated at intervals and immediately neutralized. Ethanol-chloroform 50-50 (v/v) extracts of the gastric fluid aspirated after 90 min and of all the urine specimens collected for 5 days were applied to a DEAE Sephadex LH-20 column. The radioactivity appeared in a single peak as digoxigenin in the 90 min gastric aspirate and in all urine specimens. Extensive intragastric hydrolysis of digoxin may occur under conditions of maximum acid output.

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Section: Discussionmentioning

confidence: 99%