Abstract

Astereoselective, stability indicating validated LC-assaymethod for the separation and quantification of darifenacin and its enantiomer

Author(s): M.Vishnu Murthy, K.S.V.Raghavacharyulu, Ch.Krishnaiah, Katkam Srinivas, K.Mukkanti, N.Ramesh Kumar

A simple, rapid isocratic stability indicating chiral HPLC method has been developed for the separation of R-Darifenacin fromS-Darifenacin and quantitative determination of R-Darfenacin enantiomer and Darfenacin Hydrobromide assay in bulk forms and pharmaceutical dosage forms. Forced degradation studies were performed on bulk drug sample of Darifenacin using acid (2.0 N hydrochloric acid), base (1.0 N sodiumhydroxide), oxidation (3.0%v/v hydrogen peroxide), water hydrolysis, Thermal (1050C) and photolytic degradation. Considerable degradation was observed during oxidative stress condition. Mobile phase contains n-hexane, ethanol and diethyl amine in the ratio of 75: 25: 0.05 (v/v/v). Good resolution viz. 3 min between R- and S- forms of Darifenacin was achieved with Immobilized chiral stationary phaseChiralpak IC(250mm4.6 mm ID, 5micron) column at 270Ctemperature. Flowratewas kept at 0.8 ml/min. This method was further used to determine the amount of R- Darifenacin, which was monitored by UV absorption at 230 nm. Thismethod is capable of detecting R-Darifenacin to a level of 0.08g/ml. The method was validated as per ICH guidelines.