Green method by National Environmental Methods Index and Eco-Scale Assessment for evaluation of gatifloxacin-based...

The literature reveals gaps in the availability of green analytical methods for assessing products containing gatifloxacin (GFX), a fluoroquinolone. Presently, method development is supported by tools such as the National Environmental Methods Index (NEMI) and Eco-Scale Assessment (ESA), which offer objective insights into the environmental friendliness of analytical procedures. The objective of this work was to develop and validate a green method by the NEMI and ESA to quantify GFX in eye drops using HPLC. The method utilized a C₈ column (4.6 × 150 mm, 5 μm), with a mobile phase of purified water containing 2% acetic acid and ethanol (70:30, v/v). The injection volume was 10 μL and the flow rate was 0.7 mL/min in isocratic mode at 25°C, with detection performed at 292 nm. The method demonstrated linearity in the range of 2-20 μg/mL, and precision at intra-day (relative standard deviation [RSD] 1.44%), inter-day (RSD 3.45%), and inter-analyst (RSD 2.04%) levels. It was selective regarding the adjuvants of the final product (eye drops) and under forced degradation conditions. The method was accurate (recovery 101.07%) and robust. The retention time for GFX was approximately 3.5 min. The greenness of the method, as evaluated by the NEMI, showed four green quadrants, and by ESA, it achieved a score of 88.