Development and Validation of UV Spectrophotometric Method for Simultaneous Estimation of Pregabalin and Etoricoxib in Bulk and Pharmaceutical Dosage Form and the Extension of the Developed Colorimetric Method for Estimation of Pregabalin using Smartphone Application

Abstract

A simple, sensitive, accurate, precise and reproducible method has been developed for simultaneous estimation of Pregabalin and Etoricoxib in bulk and pharmaceutical dosage form (bilayer tablet). In the method, the methanol and phosphate buffer (pH 7.2) were used as solvent as the drugs could not be extracted from bilayer tablet with single organic solvent. Also, pregabalin is not having chromophore, so it does not show absorbance in UV range. So here the pregabalin was derivatized using ethanolic ninhydrin which shows absorption maximum at 576 nm. Etoricoxib shows the absorption maximum at 284 nm. Beer Lambert’s law was obeyed over a concentration range of 2-10 μg/ml for Pregabalin (r2 = 0.9991) & 4-24 μg/ml for Etoricoxib (r2 = 0.9998). The developed method was successfully applied for the estimation of Pregabalin and Etoricoxib in commercial product bilayer tablet. The assay was found to be 99.77 and 99.96 % for Pregabalin and Etoricoxib respectively. The developed method has been validated with respect to linearity, range, accuracy & precision. Also, the developed colorimetric method was extended for the estimation of Pregabalin using mobile phone/ smartphone application and was successfully used for the assay of pharmaceutical dosage form. Keywords: Pregabalin, Etoricoxib, Ninhydrin, UV spectrophotometric, Bilayer tablet, PhotoMetrix.