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 3 days at 70 °C and 100% relative humidity. |
Appearance of the substance
The substance, originally in the form of colourless crystals or a white, crystalline powder, changes after procedure A into a solid mass and after procedure B into a paste but remaining white.
Gain of moisture
After procedure A: |
1% |
After procedure B: |
64% |
Chromatographic test
Adsorbent: Silica gel F-254
Solution applied to the plate: Substance dissolved in a mixture of methanol and water (8:2).
Solvent system:
acetone ................................. 30 volumes
toluene ................................. 20 volumes
concentrated ammonia .......... 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 A and B and the spot obtained from the reference solution of pilocarpine nitrate display the same chromatographic characteristics of migration and detection.
High performance liquid chromatography
After procedure B an impurity is detected.
Colorimetric determination
Reaction with hydroxylamine and ferric chloride.
After procedure A: |
no degradation |
After procedure B: |
25% degraded |
Conclusion
Pilocarpine nitrate is subject to decomposition under accelerated degradation conditions.
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