title: Measurement of NMDA Receptor Antagonist, CPP, in Mouse Plasma and Brain Tissue Following Systematic Administration Using Ion-Pair LCMS/MS.
abstract: (RS)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) is a competitive antagonist of the N-methyl-D-aspartate (NMDA) receptor and is routinely used with rodent models to investigate the role of NMDA receptors in brain function. This highly polar compound is difficult to separate from biological matrices. A reliable and sensitive assay was developed for the determination of CPP in plasma and tissue. In order to overcome the challenges relating to the physicochemical properties of CPP we employed an initial separation using solid phase extraction harnessing mixed-mode anion exchange. Then an ion-pair UPLC C18 separation was performed followed by MS/MS with a Waters Acquity UPLC interfaced to an AB Sciex QTrap 5500 mass spectrometer, which was operated in positive ion ESI mode. Multiple reaction monitoring (MRM) mode was utilized to detect the analyte and internal standard. The precursor to product ions used for quantitation for CPP and internal standard werem/z252.958 → 207.100 and 334.955 → 136.033, respectively. This method was applied to a pharmacokinetic study and examined brain tissue and plasma concentrations following intravenous and intraperitoneal injections of CPP. The elimination half-life (t1/2) of CPP was 8.8 minutes in plasma and 14.3 minutes in brain tissue, and the plasma to brain concentration ratio was about 18:1. This pharmacokinetic data will aid the interpretation of the vast number of studies using CPP to investigate NMDA receptor function in rodents and the method itself can be used to study many other highly polar analytes of interest.
authors: Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, WI 53706, USA.
authors: Erin
authors: E
authors: Gemperline
authors: Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, 600 Highland Ave, Madison, WI 53792, USA.
authors: Kurt
authors: K
authors: Laha
authors: School of Pharmacy, University of Wisconsin-Madison, 777 Highland Ave, Madison, WI 53705, USA.
authors: Cameron O
authors: CO
authors: Scarlett
authors: Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, 600 Highland Ave, Madison, WI 53792, USA.
authors: Robert A
authors: RA
authors: Pearce
authors: Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, WI 53706, USA ; School of Pharmacy, University of Wisconsin-Madison, 777 Highland Ave, Madison, WI 53705, USA.
authors: Lingjun
authors: L
authors: Li