A green sustainable ultrasensitive micelle-sensitized spectrofluorimetric approach for the estimation of tafamidis in different matrices at picogram levels

Tafamidis is a novel drug approved by the European Medicines Agency to treat certain forms of transthyretin amyloidosis. The current study introduces a new ultrasensitive validated spectrofluorimetric approach for tafamidis analysis in bulk, capsules, and biological fluids. The present study is considered the first spectrofluorimetry-based approach for tafamidis estimation. The proposed eco-friendly spectrofluorimetric method depended on the measurement of the enhanced native fluorescence of tafamidis exhibited at 310/370 nm without any derivatization reaction. It was found that about two-fold enhancement in the tafamidis fluorescence could be accomplished by the addition of Brij-35. Different experimental parameters affecting the fluorescence of tafamidis were examined to reach the optimal conditions and highest sensitivity. One milliliter of each of 0.02 M Britton-Robinson buffer at pH 2 and Brij-35 was added to give the maximum fluorescence intensity. The drug was successively assayed in the concentration range of (0.1–10.0 ng/mL) with a detection limit of 0.0107 ng/mL and a quantitation limit of 0.0324 ng/mL. Owing to the superior sensitivity and selectivity, the developed method was effectively applied to the quantitation of tafamidis in its capsules and spiked human plasma samples with high % recoveries and low % relative standard deviation values. The validation parameters were assessed by following the International Council for Harmonization (ICH) guidelines. Additionally, the eco-friendly property of the designed approach was considered, and the greenness was evaluated using the Green Analytical Procedure Index (GAPI) and Analytical GREENNESS metric approach (AGREE).