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 procedures A and B into a clear and colourless liquid.
Gain of moisture
After procedure A: |
50% |
After procedure B: |
60% |
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 hydrochloride 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 hydrochloride is subject to decomposition under accelerated degradation conditions.
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