Development of an Eco-friendly HPLC method for the simultaneous determination of three benzodiazepines using green mobile phase

Abstract

The analysis of the class of benzodiazepines (BDZs) is of a great importance on the levels of forensic, clinical and pharmaceutical uses. The study is focusing on the separation of three BDZs which are diazepam, clonazepam, and bromazepam using a green micellar mobile phase. It was found that the non-ionic surfactant Brij-35 can replace the organic solvent, as it decreases the retention time significantly and contributes to environmentally friendly or Eco-friendly separation procedures. The study was achieved on monolithic C18 column. Combination of sodium dodecyl sulphate (SDS): polyoxyethylene(23)lauryl ether (Brij-35) in a ratio of 50:50% v/v, was used as a mobile phase. The UV detection was set at 240 nm at a flow rate of 1.0 mL/min. The separation of diazepam, clonazepam and bromazepam was achieved in less than ten minutes even though there is no organic modifier in the mobile phase. A detailed study for the chromatographic parameters in this micellar system is carried out, in addition to a comparison with that achieved with other systems containing a single surfactant with low percent of organic modifier or other traditional mobile phase systems. Additionally, assessment of the greenness of the method is carried out using analytical eco-scale and the developed micellar HPLC method was proved to be an excellent green method for the analysis of the three drugs.