Simultaneous determination of escitalopram oxalate and eszopiclone in their combined mixture by ultraviolet spectrophotometry (Dual wavelength method)

摘要

A simple, accurate, and precise dual wavelength spectrophotometric method was developed for simultaneous determination of Escitalopram oxalate (ESC) and Eszopiclone (ESZ) in their mixtures. The principle for dual wavelength method is "the absorbance difference between two points on the mixture spectra is directly proportional to the concentration of the component of interest". The method based on determination of ESZ at 304.0 nm using its absorptivity value and ESC at 238.0 nm after deduction of absorbance due to ESZ. The two drugs follow Beer-Lambert's law over the concentration range of 5-50 μg/mL for ESC and 3-18 μg/mL for ESZ. The % estimation of the drugs was found near to 100 % representing the accuracy of the three methods. The recovery of the ESC and ESZ were found near to 100 %. Validation of the proposed methods was carried out for its accuracy, precision, specificity and ruggedness according to ICH guidelines. The proposed methods can be successfully applied in routine work for the determination of ESC and ESZ in combined dosage form.