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 4 days at 70 °C and 100% relative humidity. |
Appearance of the substance
The substance, originally in the form of white or slightly yellowish granules or a powder, changes after procedures A and B into a yellowish powder and the formation of needles is observed.
Gain of moisture
After procedure B: 80%
Chromatographic test
Adsorbent: Silica gel F-254
Solution applied to the plate: Substance dissolved in acetone-water (1:1).
Solvent system:
chloroform: .................................7 volumes
acetone: .......................................3 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 two spots obtained after procedures A and B correspond to theophylline and ethylenediamine. This method is useful to identify the substance, but not to estimate the degree of degradation.
Solubility
After procedures A and B, the solubility of the substance is modified. The insoluble part is identified as theophylline, and the degradation is assessed at 15%.
Conclusion
Aminophylline is subject to decomposition under accelerated degradation conditions.
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