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, crystalline powder changes after procedure A into a light red-brown powder and after procedure B into a black powder.
Gain of moisture
After procedures A and B: |
10% |
Chromatographic test
Adsorbent: Cellulose with a fluorescent indicator, 0.1 mm in thickness, impregnated with 0.1 H disodium edetate and dried at 100 °C for 30 minutes.
Solution applied to the plate: Substance dissolved in methanol. After application the plate is exposed to ammonia vapours for 15 minutes.
Solvent system:
n-butanol ............. 10 volumes
pyridine ............... 6 volumes
ethyl acetate ........ 6 volumes
water .................. 7 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 exposed to ammonia vapours and is examined under ultraviolet light at a wavelength of maximum output at about 365 nm.
Results: The secondary spots obtained from the solution of the sample subjected to procedure A compared to the spots obtained from the reference solution of oxytetracycline hydrochloride are more intense. The degradation was assessed at about 2%. After procedure B, additional spots appear and the secondary spots are more intense, whereas the main spot corresponding to oxytetracycline hydrochloride is much weaker.
Ultraviolet spectrophotometry
The spectrum of the solution of the sample subjected to procedure A confirms degradation.
Conclusion
Oxytetracycline hydrochloride is subject to decomposition under accelerated degradation conditions.
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