Accelerated Degradation Experiment
Conditions
Procedure A: |
30 days exposure at 50 °C and 100% relative humidity. |
Procedure B: |
30 days exposure at 50 °C and 100% relative humidity followed by 5 days at 70 °C and 100% relative humidity. |
Appearance of the substance
The substance, originally in the form of a white powder, changes after procedure A into an orange-yellow solution and after procedure B into a hard, dark brown mass.
Gain of moisture
After procedures A and B: 58%
Chromatographic test
Adsorbent: Silica gel F-254
Solution applied to the plate: Substance dissolved in a mixture composed of 5 volumes of methyl acetate, 3 volumes of acetone and 2 volumes of water to which 1% of triethylamine is added.
Solvent system: 1% of triethylamine in a mixture composed of:
methyl acetate: .............................5 volumes
acetone: ........................................3 volumes
water: ...........................................1 volume
Development conditions: The solution is allowed to migrate until the front reaches a line 15 cm from the starting line.
Detection: The plate is left in a chromatographic chamber containing some iodine crystals until spots appear.
Results: The spot obtained from the solution of the sample subjected to procedure A and the spot obtained from the reference solution of cefalexin display the same chromatographic characteristics of migration and detection. After procedure B, almost complete degradation occurs.
Conclusion
Cefalexin is subject to decomposition under accelerated degradation conditions.
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