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, crystalline powder remains unchanged after procedure A, but after procedure B changes into a brownish liquid that solidifies on cooling and after some time results into a reddish brown mass.
Gain of moisture
After procedure B: 3%
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 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 lidocaine hydrochloride 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 procedure B.
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