A method to determine two antibiotics prescribed to treat nosocomial infections in plasma and urine by micellar liquid chromatography

•A method to quantify linezolid and meropenem in plasma and urine has been developed.•It was based on direct injection – micellar liquid chromatography.•Procedure was validated by the guidelines of FDA 2018.•It was eco-friendly, rapid, inexpensive and with high sample throughput.•The influence of the composition of the mobile phase on retention factor was established. Combined prescription of the antimicrobial drugs linezolid and meropenem is a common strategy to treat multidrug-resistant nosocomial infections. We propose an innovative method to determine these two drugs in plasma and urine, based on micellar liquid chromatography. Both biological fluids were diluted in mobile phase, filtered and directly injected, without any extraction step. Using a C18 column and a mobile phase of 0.1 M sodium dodecyl sulfate – 10 % methanol, phosphate buffered at pH 3, running under isocratic mode, both antibiotics were eluted without overlapping in