Liquid chromatography determination of citalopram enantiomers using β-cyclodextrin as a chiral mobile phase additive

A reliable and specific method for the determination of citalopram enantiomers was developed and validated. Chromatographic resolution of citalopram enantiomers was made on a Shim-pack (5 μm particle size) cyanopropyl column with β-cyclodextrin (β-CD) as an effective chiral mobile phase additive. The composition of the mobile phase was (90 + 10, v/v) aqueous 0.1% triethylammonium acetate buffer, pH 4.0 (adjusted with acetic acid), and acetonitrile, containing 12 mM β-CD. The flow rate was 0.8 mL/min with ultraviolet detection at 240 nm. The effects of the mobile phase composition, concentration of β-CD, and pH of the triethylammonium acetate buffer on peak shape and resolution of the enantiomers were investigated. The calibration graphs were linear (r = 0.9999, n = 8) in the range of 1-40 μg/mL for S-(+) citalopram and R-(-) citalopram. The limit of detection values were 5.51 × 10-3 and 4.35 × 10-3 μg/mL, while the limit of quantification values were found to be 1.84 × 10-2 and 1.45 × 10-2 μg/mL for S-(+) citalopram and R-(-) citalopram, respectively.