Optimized BN-CQD fluorescence quenching method for rivaroxaban determination in pharmaceutical and biological samples: mechanistic insights, validation, and greenness assessment

Abstract

A novel, sensitive, and selective fluorescence-based method for the determination of rivaroxaban, a critical anticoagulant drug, using boron and nitrogen co-doped carbon quantum dots (BN-CQDs) as a “turn-off” fluorescence probe was developed and validated. The morphology and optical properties of the BN-CQDs were thoroughly characterized using dynamic light scattering, transmission electron microscopy, UV-vis spectroscopy, and spectrofluorimetry. A strong blue fluorescence emission of the BN-CQDs was found to be effectively quenched in the presence of rivaroxaban, with the quenching mechanism elucidated through Stern–Volmer analysis and thermodynamic studies, indicating a static quenching process. The influential factors affecting the fluorescence quenching, including pH, BN-CQDs volume, and incubation time, were optimized using response surface methodology to achieve maximal analytical performance. A valid model was obtained with an optimal desirability of 0.903. The developed method was fully validated according to ICH guidelines, demonstrating excellent linearity in the range of 20–400 ng mL⁻¹, high sensitivity with a limit of detection of 6.40 ng mL⁻¹, and satisfactory accuracy and precision. The applicability of the method was demonstrated by successfully determining rivaroxaban in pharmaceutical dosage forms and spiked human plasma samples with high recoveries. Importantly, the greenness and analytical practicality of the developed method were assessed using the AGREE and BAGI tools, respectively, showcasing its superior environmental compatibility and enhanced analytical feasibility compared to the conventional HPLC approach reported in the literature posing a viable, greener, and more practical analytical alternative for rivaroxaban determination.