Ultrasensitive analysis of the commonly abused CNS antitussive, dextromethorphan in biological fluids and dosage forms using a novel micellar-sensitized spectrofluorimetric approach: Compliance with greenness and blueness metrics.

The current study introduces the first micellar-enhanced spectrofluorimetric approach for the estimation of the commonly abused CNS antitussive, dextromethorphan (DXM) in its syrup and biological fluids. A micellar solution of sodium dodecyl sulfate (SDS) containing DXM showed high native fluorescence emission at 305 nm following excitation at 224 nm. Using SDS as a micellar system resulted in about a 2.5-fold increase in the drug's fluorescence intensity and quantum yield as well as the sensitivity of the approach. A thorough investigation was conducted into the experimental factors affecting the studied drug's spectrofluorimetric behavior. Additionally, the quantum yield of DXM was calculated, and it was found to reach up to 22 %. A calibration plot with a straight line was produced across the concentration range of 10.0-200.0 ng/mL. The suggested approach demonstrated excellent sensitivity down to the nanogram level, with 1.80 ng/mL for the detection limit and 5.47 ng/mL for the quantification limit. The drug under study was successfully analyzed in syrup using the designed approach, which yielded low %RSD values (≤0.882) and high %recoveries (99.20-101.00). The efficacy of the suggested fluorimetric technique in detecting DXM in human plasma and urine samples has been demonstrated with excellent recovery (98.12-101.35) and %RSD (≤1.39) values owing to its high sensitivity and selectivity. As DXM is one of the most commonly abused CNS antitussives, the capacity of the proposed method for its analysis in biological fluids can provide further insights for monitoring its potential abuse. The excellent greenness and eco-friendliness of the method were confirmed using GAPI and AGREE metrics, while the BAGI tool assessed its economy, practicality, and applicability. The method was fully validated according to ICH Q2 (R2) guidelines.