Streamlined spectroscopic assay for besifloxacin: A one-pot approach evaluating drugs in eye drops and aqueous humor samples based on fluorescent isoindole generation. Comprehensive evaluation of whiteness, and blueness

Besifloxacin (BSX) belongs to fluroquinolone-category antibiotic and marketed as ophthalmic suspension in the form of eye drops. BSX exert bactericidal by inhibiting DNA gyrase and topoisomerase IV which lead to retrogradation of cell division. The approach relies on the modification of BSX in an alkaline environment by tagging with o-phthalaldehyde. The fluorescent core was monitored using fluorimetric techniques at 434.6 nm after setting excitation at 337.9 nm. A proportional relationship was detected in the concentration range of 40–1100 ng mL− 1 for BSX, with values of detection and quantification limits equal to 12.8 and 38.7 ng mL− 1, respectively. The technique underwent validation and assessment following the standards outlined by the ICH. Furthermore, each experimental variable was meticulously examined and fine-tuned. The findings exhibit notable conformity to the prescribed reference procedure without any apparent inconsistencies between the two approaches. The designed probe shows good performance in the assay of BSX in eye drops and spiked aqueous humor. Finally, the whiteness and blueness of the methodology were assessed using corresponding metrics.