Bioequivalence of digoxin tablets following change in bulk supplier.

Dissolution patterns of new and old digoxin tablets and bioequivalence of such products following a change in bulk supplier were examined. The untriturated new digoxin powder showed a melting range which was almost the same as that of the old one. The particle sizes of the new digoxin powder as determined by the scanning electron photomicrography were slightly smaller than those of the old one, and the new tablets were found to have higher dissolution rate than the old tablets.The digoxin concentration in serum and saliva of 6 healthy volunteers were determined by radioimmunoassay after oral administration of digoxin tablets in a 2-way crossover design. The bioavailability of the digoxin tablets was bioequivalent. The power of variance analysis for bioequivalence test in the serum data was higher than that in the saliva data. It can be concluded that both the new and old digoxin tablets have clinically satisfactory bioavailability.