Reliable and Sensitive Stability Indicating Assay Method of Armodafinil

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.