Spectrofluorimetric Determination of Silodosin Using NBD‐Cl Reagent: Applications to Capsules and Content Uniformity Testing

Silodosin (SDN) works by specifically blocking alpha‐1 adrenergic receptors, with a strong preference for the α1A type and clinically approved for alleviating the symptoms associated with benign prostatic hyperplasia in adult patients. The medication is precisely quantified using a novel, affordable spectrofluorimetric strategy in this paper. The strategy uses a fluorogenic reagent (4‐chloro‐7‐nitrobenzofurazan, NBD‐Cl) to create a fluorescent compound called “SDN‐NBD” when it reacts with SDN. Optimal fluorescence emission was recorded at 534.7 nm (excitation: 473.4 nm) after systematic refinement of reaction variables, including pH, temperature, and NBD‐Cl concentration. The approach exhibited remarkable linearity throughout a spectrum of 40–750 ng/mL ( R 2 > 0.999), with a detection limit of 12.8 ng/mL and a quantitation limit of 38.8 ng/mL. Rigorous validation under International Council for Harmonisation (ICH) guidelines confirmed high accuracy (recovery: 98.92–101.67%) and precision (RSD < 2%). The technique was successfully applied to quantify SDN in pharmaceutical capsules, achieving consistent content uniformity (AV = 5.45). This approach is robust and avoiding costly instrumentation and chromatographic experiments. Its simplicity, reproducibility, and regulatory compliance make it promising for pharmacokinetic research, quality control, and clinical laboratories that need accurate SDN analysis in complicated matrices.