High-performance liquid chromatographic analysis of digitoxin formulations

A rapid, selective, and simple high-performance liquid chromatographic assay for digitoxin formulations is described. The method utilizes a conventional octadecyl-bonded phase column with detection at 220 nm. The isocratic solvent system resolves digitoxin from its potential degradation products and provides an accurate assay for tablet and injectable formulations with a relative standard deviation of 1.4 and 3.3%, respectively. The method is sufficiently sensitive to monitor content uniformity of tablets and the minimum quantifiable amount of digitoxin was determined to be 20 ng. The total chromatograph time was approximately 15 min.