Quantification of Olanzapine by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Olanzapine (Zyprexa™) is indicated for the treatment of schizophrenia and bipolar disorder. Olanzapine is metabolized to inactive metabolites; therefore, this assay measures the concentrations of olanzapine and internal standard, olanzapine-D3. This procedure provides instructions for quantitating levels of olanzapine in blood serum specimens. An internal standard (IS) solution consisting of the deuterated analogue of olanzapine is added to an aliquot of the patient serum or plasma, standards, and positive controls. The drugs of interest are separated from the biological fluid using solid phase extraction. The dried extracts are reconstituted in mobile phase and separated by liquid chromatography. The solution is introduced into an Agilent 6470A triple quadrupole tandem mass spectrometer via positive mode electrospray ionization (ESI) utilizing multiple reaction monitoring (MRM). Quantitation is performed by comparison to a calibration curve, using Indigo® (Ascent) software.