Employing Diaryl Pyrrolone Fluorescence for the Sensitive Spectrofluorometric Determination of Doxazosin via Condensation With Ninhydrin and Phenylacetaldehyde: Application to Dosage Form and Spiked Human Plasma With Greenness and Blueness Evaluation

A novel, sensitive, and green spectrofluorometric approach was established and validated for the estimation of doxazosin (DXN), a selective α 1 ‐adrenergic receptor blocker used in treating benign prostatic hyperplasia and hypertension. The technique relies on the condensation reaction between DXN, ninhydrin, and phenylacetaldehyde in Teorell–Stenhagen buffer (pH 7.0), forming a fluorescent diaryl pyrrolone derivative with maximum excitation and emission wavelengths at 340 and 410 nm, respectively. After optimizing the procedure variables, a calibration curve was established, and the data were statistically analyzed using linear regression, which revealed a significant correlation. The International Council for Harmonization's (ICH) recommendations were followed when validating the approach. The proposed approach showed linearity when DXN concentration was plotted versus the fluorescent response over the range of 10–120 ng mL −1 . The detection and quantitation limits were 1.8 and 5.5 ng mL −1 , respectively. The suggested approach has been effectively used for the determination of DXN in tablets and spiked human plasma with high percentage recoveries (100.40 ± 1.05 and 100.09 ± 0.91, for tablets and plasma, respectively). Furthermore, the method's greenness was verified by three up‐to‐date tools that assessed its environmental sustainability. Additionally, the practical efficiency of the technique was also evaluated using an up‐to‐date tool.