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 orange powder, changes after procedure B into a yellow-ochre powder.
Gain of moisture
Before exposure to heat and humidity: |
6% |
After procedure A: |
27% |
After procedure B: |
30% |
Chromatographic test
Adsorbent: Silica gel G
Solution applied to the plate: Substance dissolved in water.
Solvent system:
n-butanol: ...................................50 volumes
ethanol 95%: .............................25 volumes
concentrated ammonia: .............10 volumes
water: .........................................25 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: The spots obtained from the solutions of each of the samples subjected to procedures A and B and the spot obtained from the reference solution of amphotericin B display the same chromatographic characteristics of migration and detection, but the spots of the samples subjected to the test are slightly smaller and less intense.
Ultraviolet spectrophotometry
The absorption spectrum is recorded using a 0.001% solution.
| |
405 nm |
382 nm |
363 nm |
Before exposure to heat and humidity |
1.094 |
0.902 |
0.539 |
After procedure A |
0.736 |
0.607 |
0.362 |
After procedure B |
0.630 |
0.570 |
0.345 |
Conclusion
Amphotericin B is subject to decomposition under accelerated degradation conditions.
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