Stability-Indicating LC Method for the Determination of Epinastine in Bulk Drug and in Pharmaceutical Dosage Form

A novel stability-indicating LC assay method was developed and validated for quantitative determination of epinastine in bulk drugs and in pharmaceutical dosage form in the presence of degradation products generated from forced degradation studies. An isocratic, reversed phase LC method was developed to separate the drug from the degradation products, using an YMC ODS AC18 (250 mm x 4.6 mm, 5 μm) column, and 0.05% v/v trifluroacetic acid and acetonitrile (65:35 v/v) as a mobile phase. The detection was carried out at the wavelength of 220 nm. The epinastine was subjected to stress conditions of hydrolysis (acid, base), oxidation, photolysis and thermal degradation. Degradation was observed for epinastine in base, thermal and in 30% H2O2 conditions. The drug was found to be stable in the other stress conditions attempted. The degradation products were well resolved from main peak. The percentage recovery of epinastine was ranged from (99.57% to 100.25%). The developed method was validated with respect to the linearity, accuracy (recovery), precision, specificity and robustness. The forced degradation studies prove the stability indicating power of the method.