Simultaneous determination of blonanserin and its metabolite in human plasma and urine by liquid chromatography–tandem mass spectrometry: Application to a pharmacokinetic study

Blonanserin is a novel atypical antipsychotic with highly selective receptor antagonist activity to dopamine D2 and 5-HT2A. N-desethyl blonanserin (blonanserin C) is its major active metabolite in human plasma. Herein we report a new highly sensitive, selective, and rapid liquid chromatography–tandem mass spectrometry method to determine blonanserin and blonanserin C simultaneously in human plasma and urine, with N-desethyl-chlor-blonanserin (blonanserin D) as internal standard (IS). Blonanserin and blonanserin C were extracted from aliquots of plasma and urine with ethyl acetate and dichloromethane (4:1) as the solvent and chromatographic separation was performed using an Agilent Eclipse Plus C18 column. The mobile phase was composed of: acetonitrile and ammonium formate–formic acid buffer containing 5 mM ammonium formate and 0.1% formic acid (87:13, v/v). To quantify blonanserin, blonanserin C, and blonanserin D, respectively, multiple reaction monitoring (MRM) transition of m/z 368.2 → 297.2, m/z 340.2 → 297.1, and m/z 356.2 → 313.3 was performed in positive mode. The analysis time was about 5.5 min. The calibration curve was linear in the concentration range of 0.01–2 ng/ml. The lower limit of quantification reached 0.01 ng/ml. The intra and inter-day precision and relative errors were less than 8.0% and 6.6% for three QC levels in plasma and urine. The current LC–MS/MS method was validated as simple, sensitive, and accurate and has been successfully applied to investigate the pharmacokinetics of blonanserin and blonanserin C in humans.

► Simultaneous determination of blonanserin and its metabolite in human plasma and urine by LC–MS/MS was developed with short analysis time.
► Our analytical method is sensitive and the LLOQ of blonanserin and blonanserin C in plasma and urine are as very low as 0.01 ng/ml.
► Liquid–liquid extraction is developed which is simple in sample preparation and economical.
► A structural analogue is synthesized as IS. It has a consistent matrix effect to blonanserin and blonanserin C with high and stable recovery, thus the precision and accuracy are enhanced accordingly.
► It has been successfully applied to investigate the pharmacokinetics of blonanserin and blonanserin C in humans.