Determination of tritiated digoxin and metabolites in urine by liquid chromatography.
A liquid chromatographic method for the determination of digoxin, digoxigenin, its mono- and bisdigitoxoside and dihydrodigoxin in urine is described. Doses of 100 muCi of [12 alpha-3H]digoxin and 0.5 mg (640 nmol) of digoxin were administered orally to eight healthy volunteers. The compounds were extracted from urine with methylene chloride containing 3% of heptafluorobutanol. After separation, fractions corresponding to digoxin and the metabolites were measured by liquid scintillation counting. Conjugates of the glycoside metabolites were determined indirectly after pre-treatment of the samples with beta-glucuronidase-arylsulphatase. The detection limit was 0.1 nmol/l. Metabolites amounting to 0.5% of digoxin were assayed with a relative standard deviation of 5%. The advantages of the method are a high recovery in the extraction step, short separation times and the possibility of separate assay of dihydrodigoxin.
D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004077:Digoxin / Q000031:analogs & derivatives* / Q000378:metabolism / Q000652:urine*; D006801:Humans; D013997:Time Factors
C000967:dihydrodigoxin; D004077:Digoxin