Determination of olanzapine in human plasma and serum by liquid chromatography/tandem mass spectrometry.

A liquid chromatographic/tandem mass spectrometric (LC/MS/MS) assay was developed for the quantitative determination of olanzapine (LY170053, OLZ) in human plasma and serum. Bond Elut C2 solid-phase extraction cartridges (single cartridge or 96-well format), in conjunction with a positive pressure manifold, were used to extract OLZ and its internal standard, LY170222, from the biological matrix. Chromatographic resolution of OLZ from endogenous plasma interferences and its metabolites was accomplished with a MetaChem monochrom HPLC (4.6 x 150 mm, dp 5 microns). Detection was effected with a Perkin-Elmer SCIEX API III Plus mass spectrometer using positive ion atmospheric pressure chemical ionization and a multiple reaction monitoring protocol. The linear dynamic range was from 250 pg ml-1 to 50 ng ml-1 of human plasma/serum using a 0.5 ml aliquot. The inter-day precision (relative standard deviation) and accuracy (relative error) in plasma ranged from 6.26 to 7.66% and from -3.54 to 7.52%, respectively. The intra-day precision and accuracy in serum ranged from 3.46 to 8.76% and from -8.06 to 12.46%, respectively. This assay is sensitive and selective, and will be used to support both human clinical and toxicological analyses. Furthermore, using the 96-well solid-phase extraction format, sample preparation can be easily automated.

Determination of LY355703 in dog and mouse plasma by positive ion liquid chromatography/tandem mass spectrometry with atmospheric pressure chemical ionization.

A liquid chromatographic/mass spectrometric assay was developed for the determination of LY355703, a potent anti-tumor drug, in mouse and dog plasma. Empore (3M) C18 solid-phase extraction cartridges were used for sample preparation in conjunction with a positive pressure manifold. Chromatographic separation was obtained with a cyano high-performance liquid chromatographic column and detection was conducted using atmospheric pressure chemical ionization tandem mass spectrometry in the selected reaction monitoring mode. A structural analog, compound LY354504, was used as the internal standard. The assay was validated for the determination of LY355703 in mouse (ICR and NuNu) and dog (beagle) plasma. The lower and upper limits of quantitation were 2.1 and 527 ng ml-1, respectively, using a 0.1 ml plasma aliquot. The signal-to-noise ratio of a typical 2.1 ng ml-1 standard was approximately 40:1. The inter-day precision (relative standard deviation) and accuracy (relative error) derived from the analysis of validation samples at five concentrations ranged from 2.7 to 7.6% and from 4.8 to 4.5%, respectively. Throughput is approximately one sample every 3 min. This assay is simple, sensitive, accurate, precise and is being used to support toxicokinetic studies in dog and mouse.