Accelerated Degradation Experiment
Conditions
Procedure A1: |
10 days exposure at 50 °C and 100% relative humidity. |
Procedure A2: |
20 days exposure at 50 °C and 100% relative humidity. |
Procedure A3: |
30 days exposure at 50 °C and 100% relative humidity. |
Procedure B1: |
30 days exposure at 50 °C and 100% relative humidity followed by 4 days at 70 °C and 100% relative humidity. |
Procedure B2: |
30 days exposure at 50 °C and 100% relative humidity followed by 7 days at 70 °C and 100% relative humidity. |
Appearance of the substance
The substance, originally in the form of small colourless crystals or a white, crystalline powder, changes gradually after procedure A into a brown mass and after procedure B into a dark brown liquid.
Gain of moisture
Before exposure to heat and humidity: |
5% |
After procedure A1: |
16% |
After procedure A2: |
30% |
After procedure A3: |
42% |
After procedure B1: |
45% |
Chromatographic test
Adsorbent: Silica gel F-254
Solution applied to the plate: Substance dissolved in methanol.
Solvent system:
diethylamine: ..............................1 volume
xylene: ......................................10 volumes
methanol: ....................................3 volumes
ethylmethylketone: ....................10 volumes
Development condition: The solvent is allowed to migrate until the front reaches a line 10 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 left in a chromatographic chamber containing some iodine crystals until spots appear.
Results: The spots obtained from the solution of the sample subjected to procedure A1 and the spots obtained from the reference solution of codeine phosphate display the same chromatographic characteristics. Some secondary spots are observed, one of which is on the starting line. After procedure B1, additional more and less mobile spots than the main spot are revealed, indicating a degradation of about 10%.
High performance liquid chromatography
After procedures A and B: 9% degraded, calculated with reference to the dried substance.
Conclusion
Codeine phosphate is subject to decomposition under accelerated degradation conditions.
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