Green analytical chemistry and experimental design: a combined approach for the analysis of zonisamide

Green analytical chemistry principles, as well as experimental design, are a combined approach adopted to develop sensitive reproducible stability indicating HPLC method for Zonisamide (ZNS) determination. The optimal conditions for three chromatographic parameters were determined using a central composite design of the response surface. Kromasil C₁₈ column (150 mm × 4.6 mm, 5 µm) was utilized with ethanol, H₂O (30:70 v/v) as a mobile phase at a flow rate of 1 mL/min at 35 °C. Good reproducibility and high sensitivity were achieved along (0.5-10 µg/mL) concentration range. In contrast, the TLC-densitometric method was performed on aluminum plates precoated with silica gel 60F₂₅₄ as a stationary phase and chloroform: methanol: acetic acid (8:1.5:0.5 by volume) as a developing system. Reproducible results were obtained in the range of (2-10 μg/band). The chromatograms of HPLC and TLC were scanned at 280 nm and 240 nm, respectively. The suggested methods have been validated following ICH guidelines, and no statistically significant differences were detected between the results of the current study and the official USP method. It was also found that using experimental design implements the green concept by reducing the environmental impact. Finally, Eco-Scale, GAPI and AGREE were used to assess the environmental impacts of the suggested methods.