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Cefuroxime hydrolysis kinetics and stability predictions in aqueous solution
1Department of Pharmaceutical Sciences, College of Pharmacy, Medical University of South Carolina, Charleston 29425.
Journal of Pharmaceutical Sciences
|April 1, 1994
Summary
Cefuroxime degradation rates in water were predicted using pH and temperature data. Maximum stability was found between pH 4-7, with over 90% concentration remaining for 1.2 days at 25°C.
Area of Science:
- Pharmaceutical Chemistry
- Physical Chemistry
- Chemical Kinetics
Background:
- Cefuroxime is a widely used antibiotic.
- Understanding its degradation is crucial for formulation and storage.
- Hydrolysis is a primary degradation pathway in aqueous solutions.
Purpose of the Study:
- To determine cefuroxime hydrolysis rate constants.
- To predict cefuroxime degradation rates based on pH, temperature, and buffer composition.
- To establish optimal conditions for cefuroxime stability.
Main Methods:
- Hydrolysis rate constants (k) were measured across various pH and temperatures.
- Kinetic models incorporating hydrogen, hydroxyl, and spontaneous hydrolysis were developed.
- Stability-indicating HPLC assays and UV absorbance were used to quantify cefuroxime concentration.
- Arrhenius equation was used to describe temperature dependencies.
Main Results:
- A comprehensive pH-rate expression was established: k = kH(aH+) + kS1f1 + kS2f2 + kOH(aOH-).
- Formate, acetate, phosphate, and borate buffers did not catalyze degradation.
- Maximum cefuroxime stability observed between pH 4-7.
- At 25°C, over 90% of cefuroxime remained after 1.2 days in the stable pH range.
Conclusions:
- The developed kinetic models accurately predict cefuroxime hydrolysis rates.
- Optimal cefuroxime storage conditions are in the pH-independent region (pH 4-7).
- This study provides valuable data for cefuroxime formulation and shelf-life determination.