Validation of a liquid chromatographic–tandem mass spectrometric method for the measurement of (R)-1-[2,3-dihydro-2-oxo-1-pivaloylmethyl-5-(2-pyridyl)-1H-1,4-benzodiazepin-3-yl]-3-(3-methylaminophenyl)urea (YF476) in human plasma

A sensitive and specific liquid chromatographic–tandem mass spectrometric (LC–MS–MS) method has been validated for the measurement of YF476 in human plasma. The method involves a simple liquid–liquid extraction procedure, chromatography of the extracts on a C18 column, atmospheric pressure chemical ionisation and detection in the multiple reaction monitoring mode. The calibration line was linear over the concentration range 0.1 ng/ml (the limit of quantification) to 25.0 ng/ml. Intra- and inter-batch precision was <14% and intra- and inter-batch accuracy was <11% over the entire calibration range. The bioanalytical method is robust and has been used for the analysis of many samples from human subjects involved in early clinical studies (Phase I).