A fluorometric micromethod for the determination of spironolactone (I) and some of its possible metabolites was utilized to follow plasma concentrations after intravenous administration of I, canrenone (II), and potassium canrenoate (111). Spironolactone (I) was eliminated from plasma of female dogs, with a half-life of less than 10 min., and was partially converted to I1 and 111. The 7-lactone ring of I1 equilibrated with the 7-hydroxycarboxylic acid of 111, resulting in similar plasma levels of I1 2 hr. following equimolar intravenous doses of I1 and 111. Canrenone (11) represented the predominant component in plasma. Plasma concentrations of 11, following an equirnolar intravenous dose of I, were significantly smaller (-40%). Thus, I was only partially dethioacetylated to 11.
Keyphrases 0 Spirolactones-plasma levels after intravenous administration, fluorometric analysis, dogs 0 Spironolactoneplasma levels after intravenous administration, fluorometric analysis, dogs
Canrenone and potassium canrenoate-plasma levels after intravenous administration, fluorometric analysis, dogs Plasma levels-spironolactone, canrenone, and potassium canrenoate after intravenous administration, dogs Spectrophotofluorometry-analysis, spirolactones