Abstract

A specific RP-HPLC method has been proposed for the estimation of Epinastine Hydrochloride in marketed formulation (Eye Drops) in presence of Benzalkonium chloride (preservative). The method utilizes a Grace Smart RP 18 column   (250 × 4.6 mm, 5 µ) and a mixture of Acetonitrile: 1% Acetic acid buffer (pH 3 adjusted with 2% Triethanolamine) in ratio of 30:70 v/v as mobile phase maintained at a flow rate of 2.0 mL/min. Amlodipine was used as an internal standard to improve accuracy and precision of the method. The UV detection of analyte and internal standard was carried out at 240 nm. The retention time was found to be 4.17, 4.45 and 10.74 min for Epinastine hydrochloride, Benzalkonium chloride and Amlodipine respectively. The linearity was found in the concentration range of 2-100 µg/mL (r=0.999). The per cent mean recovery was found to be in range of 99.57-109.50. The LOD and LOQ were found to be 0.43326 µg/mL and 1.39291 µg/mL respectively. The proposed method was found to be specific, linear, accurate, precise, rugged and robust and found to be suitable to resolve Benzalkonium chloride commonly used preservative in eye drops.