Accelerated Degradation Experiment
Conditions
Procedure A1: |
5 days exposure at 50 °C and 100% relative humidity. |
Procedure A2: |
30 days exposure at 50 °C and 100% relative humidity. |
Procedure B: |
30 days exposure at 50 °C and 100% relative humidity followed by 7 days at 70 °C and 100% relative humidity. |
Appearance of the substance
The substance, originally in the form of a white, crystalline powder, changes after procedures A1, A2 and B into a clear, colourless and slightly viscous liquid.
Gain of moisture
Before exposure to heat and humidity: |
1% |
After procedures A2 and B: |
81% |
Chromatographic test
Adsorbent: Silica gel F-254
Solution applied to the plate: Substance dissolved in water.
Solvent system:
ethanol 95%: ..........................6 volumes
acetic acid: ..............................3 volumes
water: ......................................1 volume
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 A2 and B and the spot obtained from the reference solution of diethylcarbamazine dihydrogen citrate display the same chromatographic characteristics of migration and detection.
Conclusion
No decomposition is detected by thin-layer chromatography, but the appearance of the substance changes after procedures A1, A2 and B, due to a strong gain of moisture.
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