Accelerated Degradation Experiment

Condition

Appearance of the substance

The substance, originally in the form of white, crystalline granules or a white, crystalline powder, changes after procedures A2 and A3 into a liquid with a white crust, after homogenization a white suspension is obtained.

Gain of moisture

Chromatographic test

Adsorbent: Silica gel F-254

Solution applied to the plate: Substance dissolved in ethane 50%.

Solvent system:

toluene ............ 7 volumes
dioxan ............. 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 examined under ultraviolet, light at a wavelength of maximum output at about 254 nm.

Results: After procedure A1, an additional weak spot is observed which is less mobile than the main spot. After procedure A2, the main spot is decreased and the additional spot is estimated at a degradation of about 20%. After procedure A3, a decrease of even more importance is observed of the main spot and the significant increase in the additional spot is estimated at a degradation of about 50%.

Ultraviolet spectrophotometry

The spectrum recorded between 200 nm and 400 nm, using 0.001% solutions of each of the samples subjected to procedures A1, A2 and A3 in 0.1 N sodium hydroxide, show an absorption maximum at about 255 nm.

Conclusion

Phenobarbital sodium is subject to decomposition under accelerated degradation conditions.