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 or lightly coloured, crystalline powder, changes after procedure A into a greyish powder and after procedure B into a black powder.
Gain of moisture
Chromatographic test
Adsorbent: Silica gel F-254
Solution applied to the plate: Substance dissolved in methanol.
Solvent system:
n-butanol ................ 6 volumes
acetic acid .............. 2 volumes
water ...................... 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 spot obtained from the solution of the sample subjected to procedure A and the spot obtained from the reference solution of sodium para-aminosalicylate display the same chromatographic characteristics of migration and detection. After procedure B, a large spot with little mobility is obtained, whereas the main spot corresponding to sodium para-aminosalicylate practically disappeares.
Conclusion
Sodium para-aminosalicylate is subject to decomposition under accelerated degradation conditions.
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