First-time exploitation of Pranlukast's intrinsic fluorescence: a novel cetrimide-enhanced spectrofluorimetric platform for pharmaceutical, plasma, and content uniformity analysis

A novel, eco-friendly, and highly sensitive spectrofluorimetric method has been developed and validated for the quantification of Pranlukast (PNK) based on its intrinsic native fluorescence without the need for derivatization or fluorescent labeling. The method employs micellar enhancement with cetrimide to achieve a strong fluorescence signal at <i>λ</i> _ex = 286 nm and <i>λ</i> _em = 418 nm. Linearity was obtained in the range of 100-800 ng mL^-1 (<i>r</i> ² = 0.9993), with limits of detection (LOD) and quantification (LOQ) of 9.87 and 29.91 ng mL^-1, respectively. The method demonstrated excellent precision (RSD% < 2.0), high accuracy (mean recovery 99.2-101.4%), and selectivity in pharmaceutical formulations and spiked human plasma, with an application range of 150-600 ng mL^-1 encompassing the clinically relevant <i>C</i> _max (467 ng mL^-1). Mechanistic investigations (fluorescence profiling, Stern-Volmer analysis, and lifetime measurements) confirmed that fluorescence enhancement arises from micellar incorporation and protection against collisional quenching. Moreover, a comprehensive greenness profile was assessed using multiple tools: NEMI (fully green), GEMAM (7.487), VIGI (80), CFA (0.002 kg CO₂ per sample), and the RGBfast index (85), yielding a high overall sustainability score of 89%. The method contributes significantly to 11 UN Sustainable Development Goals (SDGs), offering a greener and more cost-effective alternative to conventional chromatographic procedures that typically rely on hazardous solvents and time-consuming steps. This work introduces the first spectrofluorimetric approach for PNK, offering advantages of simplicity, low cost, high sensitivity, and environmental sustainability compared to previously reported UV and chromatographic methods. The method's limitation lies in its reliance on a micellar medium, which may require optimization for other surfactants or biological matrices.