Tsq quantum triple stage quadrupole mass spectrometer

The experiment was performed as described⁶⁶ . Briefly, 0.4 mg male or female pooled HLM was incubated with 100 µM clozapine with the presence or absence of 2 µM ketoconazole (CYP3A4 inhibitor). After 30 min of incubation, the reaction was stopped by adding ice cold acetonitrile. Protein was precipitated twice, and the collected supernatant was stored at −20 °C. Lastly, a 10 µl portion of the supernatant was injected into the LC-MS system to determine the concentration of parent compound and metabolites⁶⁷ . The detection and quantification of clozapine and metabolites was performed using high-performance liquid chromatography (Agilent 1200 Series, Santa Clara CA) coupled with mass spectrometry (TSQ Quantum triple stage quadrupole mass spectrometer; Thermo-Electron, San Jose, CA). Chromatographic separation was performed with a Phenomenex Polar RP column, 75 × 2.0 mm, 4.0 micron, (Torrance, CA) with a mobile phase containing (60:40) DI water with 0.1% formic acid: Acetonitrile with 0.1% formic acid, at a flow rate of 500 µL/min, with the column temperature set at 30 °C. The experiment was repeated independently 3 times. Data acquisition was performed with Xcalibur Version 2.07 (Thermo-Electron). Statistical analyses were performed using the student t test. P value <0.05 was defined as a statistically significant threshold.

Serum samples collected on the fourth day of neoadjuvant treatment (Day 4) were stored at -80°C until analysis. Valspodar was quantified by liquid chromatography/mass spectroscopy (LC-MS/MS) using a high-performance liquid chromatograph (Agilent 1200 Series, Santa Clara CA) coupled with a TSQ Quantum triple stage quadrupole mass spectrometer (Thermo-Electron, San Jose, CA) as described
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