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, changes after procedure A into a grey powder and after procedure B into a liquid that solidifies on cooling into a light brown mass.
Melting point
Before exposure to heat and humidity. |
175 °C |
After procedure A: |
172 °C |
After procedure B: |
162 °C |
Gain of moisture
After procedures A and B: |
10% |
Chromatographic test
Adsorbent: Silica gel F-254
Solution applied to the plate: Substance dissolved in methanol.
Solvent system:
n-butanol ................2 volumes
acetic acid ..............1 volume
water ......................1 volume
Development conditions: The solvent is allowed to migrate until the front reaches a line 15 cm from the starting line.
Detection: The plate is examined under ultraviolet light at a wavelength of maximum output at about 254 nm and 365 nm respectively, then examined in white light after exposure to iodine vapours.
Results: The spots obtained from the solution of the sample subjected to procedure A and the spots obtained from the reference solution of imipramine hydrochloride display the same chromatographic characteristics of migration and detection. After procedure B, four additional spots are obtained under UV light at about 365 nm.
Ultraviolet spectrophotometry
After procedure A: |
no change in the spectrum |
Conclusion
Imipramine hydrochloride is subject to decompositon under accelerated degradation conditions.
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