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Photodegradation paths of cefotaxime
D A Lerner1, G Bonnefond, H Fabre
1Laboratoire de Chimie Physique, Ecole Nationale Supérieure de Chimie, Montpellier, France.
Journal of Pharmaceutical Sciences
|August 1, 1988
Summary
UV light causes cefotaxime sodium salt degradation through isomerization and photolysis. Photoisomerization efficiently produces an inactive anti-isomer without visible signs, a key concern for alkoxyimino antibiotics.
Area of Science:
- Photochemistry
- Pharmaceutical Chemistry
- Analytical Chemistry
Background:
- Cefotaxime sodium salt is a widely used antibiotic.
- Antibiotic degradation under UV light can impact efficacy and safety.
- Understanding degradation pathways is crucial for drug stability.
Purpose of the Study:
- To investigate the degradation kinetics of cefotaxime sodium salt in aqueous solution under UV irradiation.
- To elucidate the competitive processes of isomerization and photolysis.
- To highlight the significance of photoisomerization in cefotaxime degradation.
Main Methods:
- High-Performance Liquid Chromatography (HPLC) for quantitative analysis.
- Antibiotic activity assays to determine drug potency.
- UV-Vis spectroscopy to monitor spectral changes and identify degradation products.
Main Results:
- Cefotaxime degradation involves competitive isomerization and photolysis.
- Quantum yields for isomerization were measured (0.10 for syn to anti, 0.12 for anti to syn).
- A photostationary state with an anti:syn ratio of 1.2 was reached after 30 min irradiation.
- Photolysis of the delta 3-cephem ring causes yellowing, indicating molecular destruction.
Conclusions:
- Photoisomerization leads to the formation of inactive anti-cefotaxime without obvious degradation signs.
- The delta 3-cephem ring photolysis is responsible for the observed yellow coloration.
- This photoisomerization pathway is a potential degradation concern for antibiotics with alkoxyimino groups.