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Growth of microorganisms in propofol and methohexital mixtures
Bryan R Harvey1, Steven Ganzberg
1Department of Oral and Maxillofacial Surgery, Seton Hall University, St Joseph's Regional Medical Center, Paterson, NJ 07503, USA. harv04@yahoo.com
Purpose:
The purpose of this study was to evaluate the growth of 4 different microorganisms in propofol, methohexital, and 1:1 and 1:3 mixtures of propofol and methohexital.
Materials And Methods:
The microbial growth of Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Escherichia coli in 1:1 and 3:1 mixtures of methohexital and 2 types of propofol was measured for 48 hours after mixing the solutions. Two of the 4 test solutions were composed of 1% methohexital combined with Diprivan (AstraZeneca Pharmaceuticals, Wilmington, DE), which uses EDTA as a microbial growth inhibitor. The growth of the same 4 microorganisms was also evaluated in 1:1 and 3:1 mixtures of 1% methohexital and a recently introduced generic propofol marketed by Baxter Pharmaceuticals (Deerfield, IL) that uses sodium metabisulfite as a preservative.
Results:
Combining either Diprivan or generic propofol with methohexital in a 1:1 or 1:3 mixture ratio resulted in a solution that, like methohexital alone, significantly resisted the growth of C albicans, E coli, S aureus, and P aeruginosa for 48 hours.
Conclusion:
The results of our study suggest that 1:1 and 1:3 mixtures of propofol (either Diprivan or generic propofol) and methohexital behave similarly to methohexital alone by resisting growth of the microorganisms studied over the 48-hour time period. If, as has been reported elsewhere, the mixture of these 2 agents results in a solution with desirable anesthetic properties, its ability to resist microbial growth becomes clinically significant by extending the shelf-life of propofol in these mixtures.
Insights
Mixtures of propofol and methohexital resist microbial growth for 48 hours, similar to methohexital alone. This finding is significant for extending the shelf-life of propofol in these anesthetic agent combinations.
Area of Science:
- Anesthesiology
- Microbiology
- Pharmaceutical Sciences
Background:
- Propofol and methohexital are commonly used anesthetic agents.
- Understanding the microbial stability of their mixtures is crucial for safe clinical practice.
- Different propofol formulations utilize various preservatives, impacting microbial resistance.
Purpose of the Study:
- To evaluate the microbial growth of common pathogens in propofol and methohexital mixtures.
- To compare the antimicrobial properties of branded (Diprivan) and generic propofol when mixed with methohexital.
- To assess the impact of different mixture ratios (1:1 and 1:3) on microbial resistance.
Main Methods:
- Four microorganisms (Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Escherichia coli) were tested.
- Microbial growth was measured over 48 hours in solutions containing methohexital alone, propofol alone, and their mixtures.
- Two propofol types (Diprivan with EDTA, generic with sodium metabisulfite) were used in combination with methohexital.
Main Results:
- Both 1:1 and 1:3 mixtures of propofol (branded or generic) and methohexital significantly inhibited the growth of all tested microorganisms.
- The mixtures demonstrated antimicrobial properties comparable to methohexital alone.
- No significant microbial growth was observed in the mixtures over the 48-hour study period.
Conclusions:
- Propofol-methohexital mixtures exhibit robust resistance to microbial contamination.
- This antimicrobial stability is comparable to methohexital alone, suggesting enhanced shelf-life for propofol in these combinations.
- The findings support the clinical significance of propofol-methohexital mixtures, particularly regarding their extended usability due to microbial resistance.