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 colourless crystals or a white, crystalline powder changes after procedure A into pale yellow, crystalline agglomerates, the colour turning to yellow-brown after procedure B.
Gain of moisture
After procedure A: |
30% |
After procedure B: |
50% |
Chromatographic test
Adsorbent: Silica gel 60 F-254
Solution applied to the plate: Substance dissolved in methanol.
Solvent system:
ethyl acetate .............. 40 volumes
acetone ..................... 38 volumes
n-butanol .................. 24 volumes
ammonia 10% .......... 8 volumes
Development condition: 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 then at 365 nm. After spraying with a solution of potassium iodobismuthate the plate is examined in daylight.
Results: The reference solution of quinine bisulfate shows numerous spots of different intensities. After procedures A and B the intensity of some spots increase and additional secondary spots appear.
Ultraviolet spectrophotometry
No modification is observed in the spectrum or in the absorbances at the three maxima of solutions in methanol of the samples subjected to procedures A and B.
Gas-liquid chromatography
After procedures A and B: no change is observed.
Conclusion
Quinine bisulfate is subject to decomposition under accelerated degradation conditions.
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