A ROUTINE HPLC METHOD FOR MONITORING MIDAZOLAM IN SERUM

A routine high-performance liquid chromatographic method for measuring midazolam in human serum has been developed, The sample preparation p rocedure consisted of simple liquid-liquid extraction with dichloromet hane, followed by evaporation under nitrogen. The mobile phase used wa s a mixture of acetonitrile at 0.02 M and sodium acetate at pH 3.0 (80 :20, v/v) and a flow-rate of 1.2 mL/min. The separation was performed on two cyanopropyl columns (150 x 4.6 mm). The detection was by UV abs orption at 240 nm. A linear range from 10 to 1000 ng/mL and a quantifi cation limit of 7.4 ng/mL of serum was reached, The mean intra-assay a nd inter-assay reproducibility from serum sample spiked with 100 ng/mL were 4.1 and 4.7%, respectively, The recoveries from serum sample spi ked with 50, 100, 500 ng/mL were 85.46, 85.38 and 85.57%, respectively . This method was developed to allow pharmacokinetic study of midazola m in young patients in short surgical interventions.