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 yellow to greenish yellow, crystalline powder remains unchanged after procedure A, but acquires a dark beige colour with the apparition of small chestnut coloured dots after procedure B.
Gain of moisture
Before exposure to heat and humidity: |
less than 0.1% |
After procedure A: |
0.3% |
After procedure B: |
less than 0.1% |
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 still humid plate is examined directly in daylight, then under ultraviolet light at a wavelength of maximum output at about 365 nm, and after drying at about 254 nm.
Results: The spots obtained from the solution of the sample subjected to procedure A and the spot obtained from the reference solution of bephenium hydroxynaphthoate display the same chromatographic characteristics of migration and detection. After procedure B, an additional spot is observed under ultraviolet light at a wavelength of 365 nm, showing a slightly green fluorescence and is located just below the principal spot at Rf 0.67.
Ultraviolet spectrophotometry
The absorption spectrum is recorded between 200 nm and 400 nm using a 0.0005% solution of each of the samples subjected to procedures A and B in methanol.
Before exposure to heat and humidity: |
no change |
After procedures A and B: |
no change |
Solubility in methanol.
After procedure A: the solubility decreases.
Conclusion
Bephenium hydroxynaphthoate is subject to slight decomposition under accelerated degradation conditions.
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