Double isotope dilution derivative assay of digitoxin in plasma, urine, and stool of patients maintained on the drug.

Abstract

Although the cardiac glycosides have been used extensively since Withering published his observations on the effects of foxglove nearly two hundred years ago (1), their distribution and metabolism and the cellular basis of their action in man are unknown. The lack of sufficiently sensitive, chemically specific methods of assay has hampered studies of the biologic behavior of these compounds.