B-176 A Simple LC-MS/MS Method for Simultaneous Analysis of 35 Anti-Psychotics in Human Plasma for Clinical Research

Abstract Background Antipsychotic drugs (APDs) are frequently used in combination with other drugs, leading to potential pharmacokinetic and pharmacodynamic drug interactions. Many of these interactions have not been adequately studied in clinical research. This study presents a simple, cost-effective and robust LC-MS method which is based on protein precipitation for the simultaneous analysis of 35 APDs in human plasma. Methods In brief, 50 µL of plasma and 100 µL of protein precipitation solvent, a 70:30 (v:v) mixture of MeOH:0.1M ZnSO4(aq) containing stable isotope labeled internal standards was added to a microfuge tube. The samples were vortex mixed briefly and centrifuged at 18,000 g for five minutes at room temperature. Subsequently, 100 µL of the supernatant was diluted with 100 µL distilled water and the samples were mixed on a shaker for three minutes at 850 rpm prior to analysis. Samples were injected onto a Waters XSelect™ HSS C18 SB XP Column using an ACQUITY™ UPLC™ I-Class PLUS FL System and eluted using a water/methanol/formic acid/ ammonium acetate gradient. The 35 APDs were quantified using a Xevo™ TQ-S micro Mass Spectrometer operated in electrospray positive mode with multiple reaction monitoring. Results For each analyte, the method was demonstrated to be linear across calibration range, with analytical sensitivity investigations showing precise quantification (<20% CV, =15% bias). Non-linearity at all levels for all compounds was less than 10% across the targeted linearity interval. Coefficients of variation (CV) for total precision and repeatability for low, mid and high QCs were =8.7% CV and =7.4%, respectively (n = 25). Recoveries for the low and high QC across all analytes ranged from 91.5-108.7% and 85.7-112.7%, respectively. Mean extraction efficiencies for the 35 APDs ranged from 52.2%-96.9%. Conclusion A fast (less than 5 minutes per injection) and inexpensive LC-MS/MS clinical research method was developed for 35 APDs, based on protein precipitation and requiring only 50µL of plasma. The method demonstrated good recovery and extraction efficiency for each analyte, with minimal matrix effects, and total precision =8.7% CV. For Research Use Only. Not for Use in Diagnostic Procedures. ACQUITY, UPLC, XSelect and Xevo are trademarks of Waters Technologies Corporation.