Development and validation of a liquid chromatography-tandem mass spectrometry method of a panel of commonly prescribed benzodiazepines in urine samples

Benzodiazepines are one of the most prescribed for therapeutic purposes and the most abused drugs. Therefore, liquid chromatography-tandem mass spectrometry-based methods that analyze several benzodiazepines simultaneously are required. In this study, we developed a simple, full validated in-house method in a single-triple quadrupole platform SCIEX QTRAP 4500 system for the simultaneous detection and quantification of the 10 most prescribed benzodiazepines within a 10-min run time. The linear range was 12.5-500 ng/mL. All limits of detection were below 4.03 ng/mL and limits of quantitation below 12.22 ng/mL, except clobazam (7.27 and 22.04 ng/mL, respectively). Both the limit of detection and quantitation were lowest for diazepam (0.95 and 2.89 ng/mL, respectively). The method was evaluated for accuracy, precision, carry-over, recovery, stability, and matrix effects, and all validation studies met internationally acceptable criteria. The applicability of the method was proven by analyzing authentic urine samples, internal, and third-party external quality samples. This precise, accurate, shorter total run time and ease of urine sample analysis method is applicable in detecting most prescribed benzodiazepines and their metabolites even in glucuronide forms.