Accelerated Degradation Experiment

Conditions

Appearance of the substance

The material, originally in the form of an almost colourless to pale brownish yellow liquid, changes after procedure A2 into a yellow to intense orange coloured liquid and after procedure B into a light brown liquid.

Gain of moisture

After procedures A2 and B: 9.2%

Chromatographic test

Adsorbent: Silica gel F-254

Solution applied to the plate: Substance dissolved in ethanol 95%.

Solvent system:

chloroform: ...........................95 volumes
methanol: ................................5 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 examined under ultraviolet light at a wavelength of maximum output at about 254 nm, then sprayed with molybdotungstophosphate reagent and exposed to ammonia vapours.

Results: Under ultraviolet light the spots obtained from the solutions of each of the samples subjected to procedures A2 and B and the spots obtained from the reference solution of cresol display the same chromatographic characteristics of migration and detection. After spraying no secondary spots are revealed with the solution from procedure A2. After procedure B, two traces are observed, one less mobile, the other more mobile than the main spot.

Ultraviolet spectrophotometry

1. The absorption spectrum is recorded between 200 nm and 400 nm using a 0.001% solution of the samples subjected to procedures A2 and B in ethanol 95%; a maximum is observed at about 280 nm.

2. The absorption spectrum is recorded between 200 nm and 400 nm using a 0.001% solution of the samples subjected to procedures A2 and B in 0.1 N sodium hydroxide; maxima are observed at about 237 nm and 295 nm.

Results: Both spectra show no degradation.

Conclusion

No major decomposition is detected by thin-layer chromatography or by ultraviolet spectrophotometry, but the appearance changes after procedures A1, A2 and B.