Modafinil (MDF) is one of the drugs that used for the treatment of narcolepsy.
This manuscript involves the development and validation of two chromatographic stability indicating methods for MDF in the presence of its acid induced degradation.
Modafinil was degraded under different stress conditions and identification of the degradation product was performed using infrared and mass spectroscopy. The first method was thin layer chromatography where aluminum backed silica gel 60F254 plates were used and the developing system was dichloromethane- methanol (9:1, v/v). While the second method was an eco- friendly (HPLC) that utilized C-18 column and ethanol- H2O (30:70, v/v) as a mobile phase at flow rate 1 mL/min and UV detection at 220 nm.
Good linear relationships were obtained within ranges of (1-10 µg/band) and (2-10 µg/mL) for TLC-densitometry and HPLC, respectively. The obtained results were statistically compared with those of the official HPLC method and showed no significant difference with respect to their accuracy and precision at p = 0.05. Greenness scores represent excellent green analysis in comparison with the reported studies.
The proposed methods were validated according to ICH guidelines and were applied on bulk powder and pharmaceutical dosage form using eco-friendly mobile phases as the worldwide trend.
Chromatographic methods have been validated for estimation of MDF in the presence of its degradation product. Clarification of degradation pathway and the elucidation of the structure were stated for the first time. It’s the first published method using greenness assessment metrics for the analysis of MDF.

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