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 4 days at 70 °C and 100% relative humidity.
Appearance of the substance
The substance, originally in the form of a white or creamy white, crystalline powder, changes after procedures A and B into a light cream-coloured powder.
Gain of moisture
After procedures A and B: 2.5%
Adsorbent: Silica gel F-254
Solution applied to the plate: Substance dissolved in methanol.
chloroform: .....................7 volumes
acetone: ...........................3 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, or the plate is sprayed with the following reagent until yellow spots appear: 1 g of p-dimethylaminobenzaldehyde, 30 ml of ethanol 95%, 30 ml of concentrated hydrochloric acid and 180 ml of n-butanol.
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 dapsone display the same chromatographic characteristics of migration and detection. No secondary spots are revealed.
No decomposition is detected by thin-layer chromatography, but the appearance of the substance changes slightly after procedures A and B.