A two-compartment model for digoxin disposition in dogs.

The disappearance of digoxin from heart and skeletal muscle was studied in dogs using a sequential biopsy technique. The animals were injected with digoxin for five days and subsequently with 3H-digoxin for an additional three days. 12, 24, and 48 h after discontinuation of digoxin, tissue samples of left ventricle, left atrial appendage, and skeletal muscle were taken. In addition, digoxin serum levels were measured. With the help of a computer program, a mathematical model was developed for the description of the disposition and elimination of digoxin from tissue. Disappearance from plasma and tissue was consistent with a two-compartment open model.