Reverse Phase Liquid Chromatographic Method for the Quantification of Di-P-Toluoyl-D-Tartaric Acid in Escitalopram Oxalate Drug Substance

A simple and rapid high performance liquid chromatographic method has been established to quantify the optically active precipitant Di-p-Toluoyl-d-Tartaric acid (DPTTA) at very low level inEscitalopram oxalate drug substance. The method is subsequently validated to prove its suitability, sensitivity and repeatability. The high performance liquid chromatographic (HPLC) method is developed in such a way that to enhances the detection level and minimizes acquisition time by using suitable buffer of 0.02% (v/v) of Orthophosphoric acid pH 3.0±0.5 and Acetonitrile as eluent inisocratic mode. The retention time of DPTTA is about 4.0 min and the total acquisition time was less than 15 min. The optimized method was validated to prove its performance characteristics bydemonstrating selectivity, sensitivity (limit of detection and quantification), linearity, precision and accuracy. The experimentally established limit of detection and quantification was found to be 0.040μg mL^-1 and 0.120 μg mL^-1 respectively and the overall percent accuracy (recovery) of the samples evaluated at different concentration levels was found to be 99.0, indicating the sensitivity and ccuracy of this optimized HPLC method by citing the guideline requirement.