Sustainable method development for the simultaneous detection of formoterol fumarate and glycopyrrolate

A novel green high-performance liquid chromatography (HPLC) method was developed for the simultaneous quantification of formoterol fumarate and glycopyrrolate, targeting environmental sustainability in analytical procedures. Utilizing a mobile phase of 0.05 M phosphate buffer (pH 3.5) and ethanol (30:70 v/v), the method exhibited optimized chromatographic conditions with retention times of 3.703 ± 0.345 min for formoterol fumarate and 5.383 ± 0.568 min for glycopyrrolate. The detection wavelength was established at 230 nm, allowing for significant absorption of both drugs. Linearity was demonstrated over 5–15 µg/mL for formoterol fumarate and 10–30 µg/mL for glycopyrrolate, with correlation coefficients (r2) of 0.9992 and 0.9994, respectively. The limits of detection (LOD) were 0.430 µg/mL for formoterol fumarate and 0.772 µg/mL for glycopyrrolate, while the limits of quantification (LOQ) were 1.302 µg/mL and 2.187 µg/mL, respectively. System suitability tests indicated excellent precision, with %RSD values below 2%. Stability studies confirmed the robustness of the method under slight variations in chromatographic conditions. The method’s efficacy was validated through the analysis of a marketed formulation, yielding recovery rates of 98.26% ± 0.401 for FF and 97.81% ± 0.807 for GP, thereby reinforcing its applicability in routine quality control.