Multi-Metric Evaluation of a Green HPLC-PDA Method for Sibutramine Quantification in Herbal Teas

Sibutramine (SBT) is a synthetic anorectic agent formerly prescribed for obesity but withdrawn due to cardiovascular risks. Its illicit addition to herbal weight-loss products remains a major health concern. This study reports the development and validation of a green, rapid, and sensitive HPLC-PDA method for SBT quantification in herbal teas. Separation was performed on a C18 reversed-phase column (150 × 4.6 mm, 5 μm) using ethanol:water (35:65, v/v) acidified to pH 3.0 with orthophosphoric acid, under isocratic conditions (2.0 mL/min, 40°C, 10-min runtime). A matrix-matched calibration strategy was employed to minimize matrix effects. The method showed excellent linearity (R² = 0.9987) within 1.00-30.00 μg mL^-1, with LOD and LOQ of 0.06 and 0.20 μg mL^-1. The validation of the method, rigorously conducted in accordance with the ICH Q2(R2) guidelines, unequivocally confirmed its high accuracy, reproducibility, and robustness across multiple experimental conditions. Comprehensive multi-metric assessments further demonstrated the method's outstanding analytical performance, remarkable applicability, and notable environmental sustainability. Taken together, these results underscore that the method is not only highly reliable and precise but also eco-conscious, making it exceptionally well suited for routine screening and monitoring of complex herbal matrices, fully aligning with the principles of white analytical chemistry.