[Comparative bioavailability of three pharmaceutical forms of digoxin].

The bioavailability single doses (0.5 mg) from three preparations of digoxin is compared in a crossover study in nine normal volunteers. Plasma digoxin concentrations from 0 to 72 hr and urinary glycoside excretion for 96 hr are measured by radioimmunoassay. Areas under the plasma concentration-time curves are assessed according to two different statistical methods, one comparing preparations, the other comparing subjects. With the first, bioavailabilities are similar; with the second, they significantly differ. On the other hand, urinary excretions do not differ. This discrepancy is probably related to different kinetics of digoxin release from the pharmaceutical preparations, the total amount absorbed being equivalent.