Enhanced bioavailability of digoxin by gamma-cyclodextrin complexation.

Inclusion complex of digoxin with gamma-cyclodextrin (gamma-CyD) in 1:4 molar ratio was prepared, and its dissolution and absorption behaviors were compared with those of digoxin alone. The dissolution rate of digoxin in water was found to be markedly increased by gamma-CyD complexation. Bioavailability of digoxin following the oral administration of gamma-CyD complex to dogs was 5.4 times as much as that of digoxin alone. The present data did indicate improvement of dissolution and absorption characteristics of digoxin by inclusion complexation, suggesting the decrease in dose in oral digoxin therapy.