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Stability of colistimethate sodium in aqueous solution
A M Healan1, W Gray, E J Fuchs
1Division of Infectious Diseases and HIV Medicine, Case Western Reserve University, Cleveland, OH, USA. amb233@case.edu
Antimicrobial Agents and Chemotherapy
|October 17, 2012
Summary
Colistimethate sodium, used for resistant infections, breaks down into toxic compounds. Storing it at various temperatures for 24 hours showed it remained stable, preventing harmful colistin formation.
Area of Science:
- Pharmacology
- Microbiology
- Drug Stability
Background:
- Colistimethate sodium is crucial for treating multidrug-resistant Gram-negative bacterial infections.
- Spontaneous hydrolysis of colistimethate sodium yields active colistins (polymyxins E1 and E2/B).
- High concentrations of these breakdown products are linked to severe adverse effects, including nephrotoxicity and mortality.
Purpose of the Study:
- To evaluate the stability of reconstituted colistimethate sodium under various storage conditions.
- To determine the extent of colistin A and B formation over time at different temperatures.
Main Methods:
- Reconstituted colistimethate sodium solutions were prepared.
- Samples were stored at controlled temperatures (21°C, 0°C, -20°C, -70°C).
- Stability was assessed by quantifying colistin A and B formation over a 24-hour period.
Main Results:
- Colistimethate sodium demonstrated high stability across all tested temperatures.
- Formation of colistin A and B remained below 1.0% throughout the 24-hour study period.
- No significant degradation was observed at refrigerated or frozen storage conditions.
Conclusions:
- Reconstituted colistimethate sodium is stable for up to 24 hours when stored at temperatures ranging from 21°C to -70°C.
- This stability minimizes the risk of forming toxic colistin A and B, potentially improving patient safety.
- Findings support safe handling and administration protocols for colistimethate sodium in clinical settings.
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