Study the pharmacokinetics of AV‐45 in rat plasma and metabolism in liver microsomes by ultra‐performance liquid chromatography with mass spectrometry

Abstract

An ultra-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method was developed and validated to determine AV-45 in rat plasma. After the addition of the internal standard benzophenone, plasma samples were pretreated by protein precipitation. Chromatographic separation was achieved on an Acquity UPLC BEH C₁₈ column (50 × 2.1 mm, 1.7 µm) by gradient elution at a flow rate of 0.4 mL/min. Detection of analytes and internal standard (IS) was done by tandem mass spectrometry, operating in positive-ion and multiple reaction monitoring mode. The method was fully validated for its sensitivity, selectivity, accuracy and precision, matrix effect and stability study. The calibration curve showed good linearity over the concentration range 2.00-1000 ng/mL for AV-45. Intra- and inter-day precisions were less than 7.6%, and accuracy ranged from 100.6 to 107.8%. There was no matrix effect. The validated method was successfully applied to a pharmacokinetic study of AV-45 in rats. Additionally, the metabolism of AV-45 in rat liver microsomes was also studied by ultra-performance liquid chromatography combined with time-of-flight mass spectrometry (UPLC/TOF-MS). With the help of chromatographic behavior and accurate mass measurements, the metabolites were characterized.

Synthesis and In Vitro and In Vivo Evaluation of 18F-Labeled Positron Emission Tomography Tracers for Imaging Aβ Plaques

“…Subsequently, reliable MS methods were established and validated by methods of reference and by means of sensitivity, specificity, linearity, and detection limits (Figures 6a and S10). 58,59 As shown in Figure 6b,c, BIBD-124 and AV45 had low retention in both blood and brain at 30 min. However, the demethylated metabolite M1 of BIBD-124 was much less than that of AV45 at 30 min in blood.…”

Alzheimer’s Amyloid Hypothesis and Antibody Therapy: Melting Glaciers?

“…This resulted from the blood-brain barrier (BBB) brain penetrability of peripheral metabolites, as confirmed by Avid Pharmaceuticals investigators [78], with similar results expected in humans. With such a high level of brain metabolites and concomitant depletion of the parent probe, added to the in vivo radiodefluorination also reported for both [ 18 F]florbetapir and the structurally related [ 18 F]florbetaben [79], the possibility of accurate measurement of amyloid loads at the time of PET image analysis is virtually eliminated [23], even accounting for the expected metabolism translation from rodents to primates that would favor slower peripheral metabolism in humans. The rapidly increasing concentrations of brain metabolites of [ 18 F]florbetapir and [ 18 F]florbetaben produce a high background signal and hinder signal specificity for the amyloid deposition observable in in vitro experiments.…”

Amyloid-β Positron Emission Tomography Imaging Probes: A Critical Review

“…In this study [23], at least two of the [ 18 F]florbetapir metabolites identified were shown to have good blood-brain barrier (BBB) penetrability in the mouse brain. In vivo radiodefluorination was also reported to have been observed with both [ 18 F]florbetapir and the closely related probe [ 18 F]florbetaben [24]. …”