Development and validation of a liquid chromatographic method for determination of enantiomeric purity of citalopram in bulk drugs and pharmaceuticals

A simple, rapid and robust LC method for enantiospecific separation and determination of citalopram in drugs and pharmaceuticals was developed using UV and polarimetric detectors connected in series. Baseline separation with resolution > or = 3.0 was achieved within 20 min on Chiralcel OD-H (250 mm x 4.6 mm) 5 microm column using a mobile phase containing of n-hexane:2-propanol:triethylamine (TEA) (95:05:0.1 v/v/v) at a flow rate of 1.0 ml/min at 25 degrees C. Effects of 2-propanol, triethylamine and temperature on enantioselectivity and resolution of the enantiomers were evaluated. Clopidogrel hydrogen sulphate was used as an internal standard (IS) for quantitative determinations using UV detector at 240 nm. Polarimetric detector was used for identification of enantiomers. The limits of detection (LOD) and quantification (LOQ) were 0.5 and 1.3 microg/ml respectively for both the enantiomers. The linearity of the method was in the range of 50-600 microg/ml with r2 > 0.9999. The inter- and intra-day assay precision was less than 0.63% (%R.S.D.) and recoveries were in the range 99.38-100.41%. The method was validated and found to be suitable for determination enantiomeric purity of citalopram in bulk drugs and pharmaceutical formulations.