Development and validation of an HPLC-MS/MS assay for the quantitative analysis of remimazolam in critically ill patients

Remimazolam is a novel benzodiazepine which is commonly used in procedural sedation, but its pharmacokinetics in critically ill patients have not yet been unequivocally clarified. A high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) method was established and validated for the determination of the remimazolam concentration in human plasma. The plasma sample extraction method was protein precipitation. A triple quadrupole mass spectrometer equipped with an electrospray ionization source and multiple reaction monitoring was used for mass spectrometry analysis. The analytes were isolated on an ACQUITY UPLC BEH C18 column with the mobile phase A (10 mM ammonium acetate in water containing 0.2% formic acid) and mobile phase B (acetonitrile) under a gradient program. The retention time of the analyte and IS were 2.0 and 1.4 min, respectively. The linear range for quantitative analysis of remimazolam was 1.0–1000 ng/mL and the extraction recovery rate was 97.3%–99.3%. According to the Chinese Pharmacopoeia and the ICH Harmonized Guidelines for Biological Analysis Method Validation, this approach has been validated in terms of selectivity, accuracy, precision, carryover, dilution integrity, matrix effects and stability. In a population pharmacokinetic study of remimazolam that targeted patients in intensive care units, the HPLC-MS/MS method was successfully applied to the quantitative measurement of remimazolam concentrations in human plasma. This method has the advantages of simplicity of operation, reliability, and sensitivity.