Digoxin injection is available as a 250-mcg/mL solution in 2-mL ampuls and vials.3930; 3831 Each mL of solution contains digoxin 250 mcg (0.25 mg) in propylene glycol 40% (v/v) or 42.5% (w/v) and alcohol 10%, along with sodium phosphate 0.17 or 0.3% and citric acid 0.08% for pH adjustment.3930; 3931
Digoxin pediatric injection is available as a 100-mcg/mL solution in 1-mL ampuls and vials.3930 Each mL of solution contains digoxin 100 mcg (0.1 mg) in propylene glycol 42.5% (w/v) and alcohol 10%, along with dibasic sodium phosphate 0.17% and citric acid 0.08% for pH adjustment.3930
pH
Osmolality
The osmolality of digoxin pediatric injection (Burroughs Wellcome) was determined to be 9105 mOsm/kg by freezing-point depression and 5885 mOsm/kg by vapor pressure.1071
Trade Name(s)
Lanoxin
Digoxin injection is administered by intravenous injection slowly over a minimum of 5 minutes or by deep intramuscular injection.3930 Intravenous injection is the preferred parenteral route because intramuscular injection may result in severe injection site pain.3930 For intravenous injection, both concentrations of digoxin injection can be administered undiluted or diluted with a fourfold or greater volume of sterile water for injection, dextrose 5%, or sodium chloride 0.9%.3930 The use of less than a fourfold volume of diluent could lead to precipitation.3930 If a tuberculin syringe is used for very small doses, the possibility of inadvertent overdosage exists.3931 Following intravenous administration, the tuberculin syringe should not be flushed with parenteral solution.3931 If intramuscular injection is necessary, the injection should be made deep into the muscle followed by massage.3930
Intact containers of digoxin injection should be stored at controlled room temperature and protected from light.3930; 3931
The manufacturers recommend diluted solutions of digoxin be used immediately.3930; 3931
Digoxin 250-mcg/mL (Sandoz Canada) was diluted to a concentration of 50 mcg/mL (0.05 mg/mL) in sodium chloride 0.9% and in a compounded solution equivalent to the commercially-available solution containing propylene glycol 40% (w/w), ethanol 10% (w/w), sodium phosphate dibasic 0.3% (w/w), citric acid monohydrate 0.08% (w/w) and sterile water for injection.3932 The diluted solutions were packaged in glass vials with rubber stoppers and stored in mostly dark conditions under refrigeration (3 to 7°C) or at room temperature (23 to 27°C) with 55 to 65% relative humidity for up to 180 days.3932 All solutions were stable and remained clear, colorless, and free of particulate matter throughout the study.3932 Digoxin diluted in sodium chloride 0.9% lost 5.3 or 6.5% in 180 days when stored under refrigeration or at room temperature, respectively.3932 Digoxin diluted in the compounded commercially-available equivalent solution lost 5.1 or 5.4% in 180 days when stored under refrigeration or at room temperature, respectively.3932
pH Effects
Digoxin is hydrolyzed in acidic solutions with a pH less than 3. At pH 5 to 8, however, digoxin is not hydrolyzed in aqueous solutions.798; 799; 800; 801
Plasticizer Leaching
Digoxin (Elkins-Sinn) 0.04 mg/mL in dextrose 5% did not leach diethylhexyl phthalate (DEHP) plasticizer from 50-mL polyvinyl chloride (PVC) bags in 24 hours at 24°C.1683
Filtration
Digoxin (Burroughs Wellcome) 1 mg/L in dextrose 5%, sodium chloride 0.9%, and Ringer’s injection, lactated filtered over 12 hours through a 5-µm stainless steel depth filter (Argyle Filter Connector), a 0.22-µm cellulose ester membrane filter (Ivex-2 Filter Set), and a 0.22-µm polycarbonate membrane filter (In-Sure Filter Set), showed no significant reduction due to binding to the filters.320
In another evaluation, digoxin (Burroughs Wellcome) 3 mg/L in dextrose 5% and sodium chloride 0.9% did not display significant sorption to a 0.45-µm cellulose membrane filter (Abbott S-A-I-F) during an 8-hour simulated infusion.567
Digoxin (Wellcome) 1 mcg/mL in dextrose 5% and sodium chloride 0.9% was delivered over 8 hours through 4 kinds of 0.2-µm membrane filters varying in size and composition. In the first 20 minutes, digoxin concentration losses were 10 to 23% through the Sterifix filter and 24 to 32% through the Pall ELD-96LL filter. However, losses of 63 to 73% occurred in the first 20 minutes with the Ivex-HP and Pall FAE-020LL filters. Subsequent digoxin levels returned to the original concentration when the binding sites became saturated.1399
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