Multi-Dose Vial Stability for Gentamicin and Dexamethasone After Opening
Multi-dose vials of gentamicin and dexamethasone combination solutions can be used for up to 28 days after opening when stored at room temperature (25°C), based on stability data demonstrating maintained chemical stability and antibacterial efficacy throughout this period. 1
Evidence for 28-Day Stability
The most direct evidence comes from a 2023 study that specifically evaluated compounded solutions of gentamicin (3 mg/mL, 0.3%) with dexamethasone (1 mg/mL, 0.1%) stored at room temperature for 28 days. 1
Key findings supporting 28-day use:
- Liquid chromatography tandem mass spectrometry confirmed chemical stability of both gentamicin and dexamethasone for the full 28-day period 1
- Bactericidal efficacy against Staphylococcus pseudintermedius showed no significant differences between Day 0, Day 14, and Day 28 1
- Solutions maintained consistent antimicrobial activity throughout the storage period when tested in triplicate 1
Storage Conditions
Room temperature storage (25°C) is appropriate for these combination solutions. 1
- No refrigeration is required for maintaining stability 1
- Solutions should be protected from light and contamination during storage
- Multi-dose vials must be handled with aseptic technique to prevent bacterial contamination
Clinical Context and Limitations
While the 28-day stability data is robust for the specific formulation tested (gentamicin 0.3% with dexamethasone 0.1% in normal saline), this represents veterinary dermatology research for otic preparations. 1
Important caveats:
- Different concentrations or formulations may have different stability profiles
- Manufacturer recommendations for specific commercial products should be followed when available
- If visible particulates, discoloration, or cloudiness develop, the vial should be discarded regardless of time elapsed
- Contamination risk increases with each entry into a multi-dose vial, making proper aseptic technique essential
Practical Recommendations
For compounded gentamicin-dexamethasone solutions: Use within 28 days of preparation when stored at room temperature, based on demonstrated chemical and microbiological stability. 1
For commercial multi-dose vials: Follow manufacturer-specific beyond-use dating, which typically ranges from 28 days after first puncture for preserved formulations, though this may vary by product.
The 28-day timeframe represents the maximum duration supported by stability testing data and should not be exceeded without specific evidence for the particular formulation being used. 1