A Stability-Indicating Liquid Chromatographic Method for the Quantification of New Anti-Epileptic Drug Lacosamide and its Intermediates

A simple, selective, precise, and stability-indicating high performance liquid chromatography (HPLC) method has been established and validated for the determination of S (–) Enantiomer in Lacosamide drug substance. The chromatographic system used normal phase DAICEL Chiralcel OD-H column with UV-Vis detection at 210 nm. The mobile phase was a mixture of n–hexane–ethanol, 74:6 (%, v/v) and this mixture was transferred to isopropyl alcohol–trifluoroacetic acid in the ratio of 72:6:0.08 (%, v/v). The method is validated for its specificity, precision, accuracy, linearity and ruggedness. Regression analysis data for the calibration plots were indicative of good linear relationships between response and concentration over the range 0.0174μg mL–1 – 5.398 μg mL–1. The correlation coefficient, r2, was 0.9994 and 0.9988. The value of slop and intercept of the calibration plot was 79403 and -16673. The limit of detection and quantitation were 0.087 ± 7.18 μg mL–1 and 0.263 ± 3.68 μg mL–1. Statistical analysis proved the method is repeatable, selective, and accurate for estimation of S (–) Enantiomer in Lacosamide drug substance and its intermediates. Because the method could effectively separate the drug from their possible impurities like dibenzyl urea, benzyl acetamide, desmethyl, diacetyl and methylbenzyl serine, it can be used as a stability indicating method.