Serum concentrations of digoxin entrapped in liposomes after intravenous administration in dogs.

1. Digoxin was associated into phosphotidylcholine liposomes at concentrations of 28-33 mol% in Hank's Buffer, pH 7.4 at 28 degrees C. 2. Digoxin-liposomes (digoxin concentration 0.022 mg/kg per dog per day) administered intravenously in five adult male dogs attained therapeutic serum concentrations (0.7-3.0 ng/ml) beginning with day 1 of administration. 3. Digoxin serum concentrations obtained by intravenous digoxin-liposomes compared favorably with normal oral digoxin administration (0.022 mg/kg per dog per day) in all 5 dogs monitoring serum digoxin levels for 7 days showed no significant (P < 0.05) differences in mean serum digoxin concentrations +/- s.e.m. on 6 of 7 days of treatments.