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Kinetics of digoxin stability in aqueous solution.

L A Sternson·R D Shaffer
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Abstract

Digoxin hydrolysis was studied as a function of pH. Conversion of digoxin to digoxigenin was followed by high-pressure liquid chromatography and shown to proceed by the initial loss of one, two, or three sugars. The hydrolysis rate was directly proportional to parent drug concentration and hydrogen-ion activity. The individual hydrolysis rate constants of digoxin, digoxigenin bisdigitoxoside, and digoxigenin monodigitoxoside were determined by a simplex fitting procedure. Data are presented suggesting that at least some variation in the bioavailability of orally administered digoxin arises from observed variations in gastric pH; these variations influence the extent to which hydrolysis occurs and, thus, modify the composition of digoxin species available for absorption.

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Chemical PhenomenaChemistryChromatography, High Pressure LiquidDigoxigeninDigoxinDrug StabilityHydrogen-Ion ConcentrationHydrolysisKineticsSolutionsJournal Article

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L A Sternson, R D Shaffer. 1978. Kinetics of digoxin stability in aqueous solution.. https://doi.org/10.1002/jps.2600670313

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