Stability of Compounded Digoxin Solution 0.05 mg/mL for Injection

Area of Science:

• Pharmaceutical Science
• Drug Stability
• Pediatric Formulations

Background:

• Commercial pediatric digoxin injection (0.05 mg/mL) was discontinued in 2015.
• Only adult concentration (0.25 mg/mL) is available, necessitating stable diluted formulations.
• No prior studies documented long-term chemical stability of diluted digoxin injection.

Purpose of the Study:

• To assess the chemical stability of a compounded digoxin injection (0.05 mg/mL).
• To evaluate stability in two different vehicles (normal saline and a commercial vehicle copy).
• To determine stability at two storage temperatures (5°C and 25°C) over 180 days.

Main Methods:

• Compounded digoxin 0.05 mg/mL by diluting the 0.25 mg/mL concentration.
• Stored solutions in normal saline and a commercial vehicle copy.
• Analyzed chemical stability via HPLC-UV at multiple time points up to 180 days.
• Assessed organoleptic changes, particulate matter, and sterility.

Main Results:

• Digoxin concentration remained above 90% of the initial concentration for all preparations throughout 180 days.
• No observed organoleptic changes or particulate matter issues.
• All samples met sterility specifications.

Conclusions:

• Compounded digoxin 0.05 mg/mL is chemically stable for at least 180 days.
• Stability was confirmed in both normal saline and a commercial vehicle copy.
• This provides a stable, accessible option for pediatric digoxin injection.