Analysis of escitalopram oxalate by various analytical methods

The main objective of this thesis is development of new analytical methods to determine escitalopram oxalate (ESC-OX) in pharmaceutical formulations, raw material and biological fluids. For this purpose, a novel HPLC method was developed and validated for determination of ESC-OX besides its six impurities. The applicability of the method was initially tested on 12 different columns which were having various surface chemistries and particle characteristics (i.e., fully porous or core-shell particle structure). Among these, six best-performing HPLC columns were selected for further comparison studies. Acceptable separation was obtained in all cases by using acetonitrile: methanol: water: phosphate buffer solution (pH 3.5, 50 mM) (25:5:20:50, v/v/v/v) mixture as mobile phase, with a flow rate of 1.2 mL min-1. The analytes were monitored at 210 nm by using an UV-visible detector. The core-shell phenyl-hexyl phase was arisen as a better performing alternative in term of separation efficiency, on the well-known industry standard C18 and relatively new PFP phases. On the other hand, quantification of ESC-OX in human urine and pharmaceutical dosage forms using different analytical techniques such as Differential Pulse Voltammetry, Capillary Electrophoresis and Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry was realized. The statistical evaluation of all developed methods showed that there was no significant difference between these methods for the quantification of the ESC-OX.