Translational value of liquid chromatography coupled with tandem mass spectrometry-based quantitative proteomics for in vitro–in vivo extrapolation of drug metabolism and transport and considerations in selecting appropriate techniques

Abstract

Introduction: Drug-metabolizing enzymes and transporters play an important role in drug absorption, distribution, metabolism and excretion and, consequently, they influence drug efficacy and toxicity. Quantification of drug-metabolizing enzymes and transporters in various tissues is therefore essential for comprehensive elucidation of drug absorption, distribution, metabolism and excretion. Recent advances in liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) have improved the quantification of pharmacologically relevant proteins.

Areas covered: This report presents an overview of mass spectrometry-based methods currently used for the quantification of drug-metabolizing enzymes and drug transporters, mainly focusing on applications and cost associated with various quantitative strategies based on stable isotope-labeled standards (absolute quantification peptide standards, quantification concatemers, protein standards for absolute quantification) and label-free analysis.

Expert opinion: In mass spectrometry, there is no simple relationship between signal intensity and analyte concentration. Proteomic strategies are therefore complex and several factors need to be considered when selecting the most appropriate method for an intended application, including the number of proteins and samples. Quantitative strategies require appropriate mass spectrometry platforms, yet choice is often limited by the availability of appropriate instrumentation. Quantitative proteomics research requires specialist practical skills and there is a pressing need to dedicate more effort and investment to training personnel in this area. Large-scale multicenter collaborations are also needed to standardize quantitative strategies in order to improve physiologically based pharmacokinetic models.

Keywords:

• drug transporters
• drug-metabolizing enzymes
• label-free strategies
• quantitative proteomics
• stable-isotope dilution strategies (AQUA/QconCAT/PSAQ)

Declaration of interest

The authors were supported by the University of Manchester. A Rostami-Hodjegan’s post is 50% funded by Certara Ltd. E Savill (Certara Ltd) provided editorial assistance. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Notes

This box summarizes key points contained in the article.