Kinetics of digoxin stability in aqueous solution

J Pharm Sci. 1978 Mar;67(3):327-30. doi: 10.1002/jps.2600670313.


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.

MeSH terms

  • Chemical Phenomena
  • Chemistry
  • Chromatography, High Pressure Liquid
  • Digoxigenin / analysis
  • Digoxin / analysis*
  • Drug Stability
  • Hydrogen-Ion Concentration
  • Hydrolysis
  • Kinetics
  • Solutions


  • Solutions
  • Digoxin
  • Digoxigenin