Simple method for the determination of benzodiazepines in human body fluids by high-performance liquid chromatography–mass spectrometry Original Research Article

Three benzodiazepines, etizolam, brotizolam and lorazepam, have been analyzed from human plasma and urine samples by high-performance liquid chromatography–mass spectrometry (HPLC–MS) with a new polymer column (MSpak GF), which enabled direct injection of crude biological samples. The recoveries of the three benzodiazepines spiked into plasma and urine were 81.7–90.7 and 78.7–91.5%, respectively. The regression equations for the three benzodiazepines showed excellent linearity in the range 10–500 ng ml−1 of plasma or urine. The detection limits were 2 ng ml−1 for etizolam and brotizolam, 5 ng ml−1 for lorazepam in both samples. The intra- and inter-day precisions for plasma and urine were not greater than 12.7%. The data obtained from determination of the benzodiazepines in rat plasma after oral administration of the drugs are also presented.