Isolation and quantitation of picomole quantities of digoxin, digitoxin and their metabolites by high-pressure liquid chromatography.

The following high-pressure liquid chromatographic (HPLC) separations are described: (1) isocratic separation of digoxin and its metabolites, (2) isocratic separation of digitoxin and its metabolites, (3) gradient elution separation of digoxin, digitoxin and their metabolites, and (4) gradient elution separation of gitoxin from digoxin and its metabolites. These methods utilize a multi-wavelength UV detector set at 220 nm and a reversed-phase column with various mixtures of acetonitrile and water as the mobile phase. The feasibility of using these HPLC methods as qualitative and quantitative techniques for digitalis glycosides is discussed.