Turn-on fluorescence determination of etoricoxib in pharmaceutical matrices and spiked human plasma with greenness/blueness evaluation.

Etoricoxib (ERX) is a potent anti-inflammatory and antipyretic medication that has recently been found to possess antitumor effects. The current work aims to establish the first spectrofluorimetric approach for ERX determination. The method is quick, eco-friendly, and greatly sensitive, and applied for the analysis of pharmaceutical tablets and in spiked human plasma. The approach relies on measuring the strong inherent fluorescence of ERX at an emission peak of 380 nm when excited at 255 nm. The fluorescence was enhanced by 10-fold in the presence of slightly acidic buffered media (pH 3.5). The dependence of fluorescence intensity on the pH of the medium was employed to calculate the pKa value of ERX. The proposed approach allows for the detection of ERX at concentrations as low as 1.39 ng mL-1. The calibration plot showed linearity across the range of 5-120 ng mL-1, with a correlation coefficient of 0.9998. The limit of quantitation was 4.22 ng mL-1. Moreover, the method's greenness and environmental safety were evaluated utilizing different metrics.