Simultaneous Estimation of Tolperisone and Etoricoxib in Bulk and Tablet Dosage Form by Spectrophotometric Methods

Present study deals with simultaneous determination of Tolperisone and Etoricoxib in their binary mixture and their tablet dosage form by UV-VIS spectrophotometry based on the additivity of absorbance of drugs. The drugs show maximum absorbance at 255 nm (λ1) for Tolperisone and 275 nm (λ2) for Etoricoxib in methanol so these wavelengths were selected for further analysis by simultaneous equation method. For absorbance ratio method 245 nm was selected as λ1 (isobestic point) and 275 nm as λ2. Matrix was drawn using the standard absorptivity values obtained at both wavelengths, the amount of drug in the sample was calculated by solving matrix using simultaneous equation method and absorbance ratio method. Also, estimation was done by first derivative spectroscopy method where estimation of drugs was carried at zero crossing point of other drug. Drugs obey the Beers-Lambert’s law at these selected wavelengths of maximum and found to be linear in the range of 5-30 µg/mL for Tolperisone while 2-12 µg/mL for Etoricoxib. The developed methods were validated as per ICH guidelines. The precision was carried out at two level viz intra-day and inter-day for which the RSD was found within limit (<%2). Recovery study was carried out on the developed method and the recovery was found to be in the range of 99.0 – 101.0 %. Methods were found to be simple, sensitive, precise and accurate. The developed methods can be applied for the routine analysis of the Tolperisone and Etoricoxib in bulk and their formulation.