<p>Finerenone, a third-generation selective non-steroidal mineralocorticoid receptor antagonist, is used in the management of diabetic kidney disease, with its efficacy further extended to reducing cardiovascular events in clinical trials. Silver nanoparticles (AgNPs) have received considerable attention for analytical and sensing applications because of their distinctive optical and surface properties, particularly surface plasmon resonance. In this study, AgNPs were green synthesized by the reduction of silver ions using gallic acid in basic media. The NPs were then characterized using dynamic light scattering and transmission electron microscopy, revealing an average size in the range ~ 10–30 nm and the zeta potential to be − 28 mV indicating the stability of the nanoparticles. The synthesized AgNPs were then employed in the determination of finerenone in bulk by correlating the decrease in absorbance at 394.5 nm with drug concentration. The method was linear in the range 6.00 × 10^–7–6.00 × 10^–6 M with a limit of detection of 1.96 × 10^–7 M and a limit of quantification of 5.94 × 10^–7 M. The proposed approach was validated in accordance with International Council for Harmonization (ICH) requirements and successfully applied to the quantification of finerenone in both marketed dosage forms and spiked human plasma samples. Furthermore, the analytical eco-scale was used to assess the method’s greenness, and it demonstrated excellent compliance with green analytical chemistry (GAC) principles.</p> Graphical abstract <p></p>