A green HPLC method for the determination of torasemide in pharmaceutical dosage forms: Development, validation, and greenness assessment

Two HPLC methods were developed for the determination of torasemide in pharmaceutical products. In the first method, a C18 column whose temperature was kept constant at 25 °C was used. A combination of 0.1% formic acid solution in water and acetonitrile (50/50, v/v) was used as the mobile phase, and isocratic elution was performed at a flow rate of 1.0 mL min-1. Detection was carried out at 288 nm using the UV detector. Although all other conditions are the same as in the first method, the only difference in the second method is that ethanol is used instead of acetonitrile as the organic modifier in the mobile phase. HPLC methods were validated in accordance with ICH guidelines. Correlation coefficients were greater than 0.999 in the concentration range of 5-30 mg mL-1. Later, HPLC methods were applied to pharmaceutical formulations. Results were compared using the student (t) test for means and the Fischer (F) test for standard deviations. No significant differences were observed between methods. Additionally, a greenness evaluation of the developed methods was carried out using AGREE software. As a result, the latter method was proposed as an excellent eco-friendly alternative for the determination of torasemide in pharmaceuticals. KEY WORDS: Green HPLC, Analytical method, Torasemide, Pharmaceuticals   Bull. Chem. Soc. Ethiop. 2024, 38(1), 11-25. DOI: https://dx.doi.org/10.4314/bcse.v38i1.2