Accelerated Degradation Experiment
30 days exposure at 50 °C and 100% relative humidity.
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 dark yellow powder and after procedure B into a dark brown powder.
Gain of moisture
After procedures A and B: 15%
Adsorbent: Cellulose with a fluorescent indicator, 0.1 mm in thickness, impregnated with 0.1 M 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.
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 tetracycline hydrochloride are more intense. The secondary spots correspond to anhydrotetracycline and to epianhydrotetracycline. After procedure B, the secondary spots are intensified indicating gross degradation.
Tetracycline hydrochloride is subject to decomposition under accelerated degradation conditions.