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. |
Appearance of the substance
The substance, originally in the form of a white, fine crystalline powder changes after procedure A1 into a yellowish white powder with yellow spots, after procedure A2 into a light yellow mass containing some air bubbles, the consistency of which is gum-like at 50 °C and hard at room temperature and after procedure A3 into a thick yellow syrup.
Gain of moisture
Before exposure to heat and humidity for the substance containing 2 moles of water: |
4.8% |
After procedure A3: |
26% |
Chromatographic test
Adsorbent: Silica gel F-254
Solution applied to the plate: Substance dissolved in water.
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: After procedure A1, the main spot is slightly deformed and a more intense tailing is observed by comparison with the spots obtained from the reference solution of phenoxymethylpenicillin calcium. After procedure A2, the intensity of the main spot has decreased indicating a degradation of about 50%. Several more mobile and less mobile spots than the main spots are also observed. After procedure A3, the intensity of the main spot has decreased even more, indicating a degradation of more than 50% but the chromatogram resembling otherwise the one after procedure A2.
Conclusion
Phenoxymethylpenicillin calcium is subject to decomposition under accelerated degradation conditions, the decomposition being estimated at about 50% after procedure A2.
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