Distribution of SC-4453, a new semi-synthetic derivative of digoxin, following an infusion preceded by an i.v. loading dose in the guinea-pig. Binding to plasma proteins.

The tissue distribution of 12 alpha-[3H]SC-4453 was studied in the guinea-pig after a 15 hours infusion at the rate of 4 micrograms/h/kg, preceded by an IV loading dose. At the end of the infusion, at the steady state, the skeletal muscle apparently presented the highest concentration of SC-4453 (24 ng/g) and the brain the lowest (1.2 ng/g), which demonstrates the presence of a blood-brain barrier to this compound. Our results also show that this new semi-synthetic cardiotonic presents a weak affinity to plasma proteins (25%).