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°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.