Exploring fluorescence of metal nanoparticles for effective utility in drug sensing: A Promising ''on-off'' fluorescence probe for analysis of cephalosporins is fabricated.

A promising fluorescent nano sensor was fabricated exploiting the unique optical and physicochemical properties of silver nanoparticles (AgNPs). AgNPs were prepared following a chemical reduction technique to get a highly water-soluble nano sensor, stable for at least 1 month without the need of organic stabilizers. Full characterization of AgNPs was done using different spectroscopic and microscopic techniques. They exhibit excellent water solubility, physicochemical and optical properties, enabling them to be successfully applied in chemical sensing of drugs. The prepared AgNPs could be conceived as a fluorescent probe for the fluorimetric determination of two commonly administered cephalosporins ceftriaxone (CTX) and cefepime (CFP) based on the quenching behavior of the fluorescence omitting the need for pre-derivatization or chromogenic reagents. The fluorescence intensity of AgNPs at 485 nm after excitation at 242 nm was quantitively quenched upon increasingly adding the studied drugs over the concentration ranges of 1-10 µg/mL and 0.9-9 µg/mL with detection limits of 0.178 µg/mL and 0.145 µg/mL for CTX and CFP, respectively. The quenching mechanisms were investigated and illustrated. The influence of different experimental parameters was studied and optimized. The suggested sensor provides an innovative, sensitive, and eco-friendly approach for the assay of the drugs in their pharmaceutical vials and quality control laboratories with excellent % recoveries of 99.88 ± 1.15, 99.95 ± 1.15 for CTX and CFP, respectively. The method was validated in accordance with ICH Q R recommendations. The greenness evaluation was performed through both Eco-Scale and GAPI revealing the green criteria of the developed method.