Objective: A reliable RP-HPLC SIAM (stability indicating assay method) was developed for the approximation of armodafinil in presence of its degradation product in pharmaceutical dosage forms. Materials and Methods: Mobile phase composition of water and methanol (10% v/v OPA) 55:45 % v/v was used for separation by using C8, (250 x 4.6 mm, 5μm) column. Eluents were detected at 225 nm at 1ml/min. Stress studies were performed using acid, base, oxidizing agents, light, and heat to get sufficient degradation about 10-20%. Results: A total of six degradation products were detected and were well separated from active drug. The linearity was found in between 10 – 150 mcg/ml. The LOD, LOQ were found as 0.78, 2.37 μg/ml respectively. The % RSD for precision study was less than 2 % the accuracy by the recovery study was 98-102%. The ARM was found to more sensitive to base hydrolysis followed by acid and photolytic degradation. In acid hydrolysis, four major degradants and rest of them are stress sensitive. Conclusion: It is concluded that the developed method is a specific stability indicating assay, suitable to quantify armodafinil in presence of six degradants. Notably, this method represented degradation product even in thermal and oxidation stress unlike other reported methods.
Key words: Armodafinil, Stability indicating, RP-HPLC method, Degradation studies.