Response surface design as a powerful tool for the development of environmentally benign HPLC methods for the determination of two antihypertensive combinations: Greenness assessment by two green analytical chemistry evaluation tools.

Interest in implementing green chemistry principles in analytical chemistry has grown dramatically in the past few years. The solvents used have the major influence on the greenness of the method. Most conventional high-performance liquid chromatography methods employed utilize solvents that are "hazardous for the environment". In the present study, two-factor three-level response surface design was exploited to develop eco-friendly chromatographic methods for two different mixtures. The first one was atorvastatin and amlodipine and the second one was amlodipine, perindopril, and indapamide. As it is nontoxic to the environment, ethanol was used as the organic modifier in the mobile phase. The separation of the first mixture was attained using phosphate buffer (pH 7)/ethanol (42:58 v/v), and the second mixture was fully resolved using phosphate buffer (pH 5)/ethanol (40:60 v/v). The use of high-performance liquid chromatography allows excellent resolution in a short run time, hence, less waste was produced. The greenness of the developed methods was assessed by two evaluation tools, namely, National Environmental Methods Index and analytical eco-scale, and found to be excellent green analytical methods. Moreover, the developed methods were compared with other reported methods regarding accuracy and greenness and were found to be perfect alternatives to reported methods for separation and quantification of the mixtures.