Accelerated Degradation Experiment
Conditions
Procedure A1: |
10 days exposure at 50 °C and 100% relative humidity. |
Procedure A2: |
20 days exposure at 50 °C and 100% relative humidity. |
Procedure A3: |
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 or almost white powder or waxy solid, changes after procedure A1 into a syrupy liquid, after procedure A2 into a syrupy liquid containing small suspended droplets, after procedure A3 into two phases forming an emulsion and after procedure B into a homogenous liquid.
Gain of moisture
After procedure A3: |
24.5% |
After procedure B: |
15% |
Chromatographic test
Adsorbent: Silica gel F-254
Solution applied to the plate: Substance dissolved in water.
Solvent system:
chloroform: ............................8 volumes
volumes acetone: ...................2 volumes
Development conditions: The solvent 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 spots obtained from the solutions of each of the samples subjected to procedures A1, A2, A3, and B, and the spots obtained from the reference solution of ethosuximide display the same chromatographic characteristics of migration and detection. No secondary spots are revealed.
Ultraviolet spectrophotometry
The absorbance is measured at about 248 nm using a solution in ethanol 95%.
After procedures A and B: no degradation is observed, taking the content of moisture into consideration.
Conclusion
No decomposition is detected by thin-layer chromatography, but the appearance of the substance changes after procedures A and B.
Chargement en cours...
