P-glycoprotein Membrane Transporter: Accurate Quantification

Pharmaron poster on targeted proteomics for P-glycoprotein membrane transporter quantification using LC-MS/MS in vitro and ex vivo with detailed charts and pathways.

Poster Authors:

Chunyan Han, Jiafu Mu, Rong Zhang, Xingjin Jiao, Haowen Li, Jiawei Zhang, Qipeng He, Aocheng He, Qiujin Ma, Yingying Shi, Yangyang Zhang, Chenglin Li, Mandy Xu

Pharmaron Beijing Co., Ltd. (China)

Accurately measuring P-glycoprotein membrane transporter levels is essential for understanding drug efflux and predicting absorption across biological barriers. Pharmaron’s targeted proteomics platform, powered by LC-MS/MS, delivers precise quantification of P-gp expression levels in both in vitro and ex vivo models. Download the full poster to learn how this platform supports IVIVE (in vitro–in vivo extrapolation) with unmatched reliability.

Why P-glycoprotein Membrane Transporter Expression Levels Matter in Drug Discovery

P-glycoprotein (P-gp, also known as MDR1 or ABCB1) plays a central role in drug absorption, distribution and excretion by actively transporting compounds across cell membranes. It’s highly expressed in the gut, liver, kidneys and blood–brain barrier. Quantifying P-gp membrane transporter abundance is critical in early ADMET profiling, especially when predicting drug–drug interactions, oral bioavailability and CNS penetration.

Pharmaron’s platform focuses on reliable quantification of P-gp using targeted proteomics, enabling better modeling for transporter kinetics and IVIVE.

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Advanced Targeted Proteomics for P-gp Quantification

Highlights of the LC-MS/MS-based approach:

In silico peptide selection: IATEAIENFR and STVVQLLER chosen via UniProt, BLAST and ExPASy
Sample types: Caco-2 cells (Transwell inserts) and rat jejunal enterocytes (EDTA isolation)
Protein extraction: Mem-PER™ Plus kit, followed by reduction, alkylation and tryptic digestion
Detection method: Absolute quantification via LC-MS/MS using multiple reaction monitoring (MRM)

Precision in Quantifying P-gp Expression Levels

Standard curves for both peptides showed excellent linearity (R² = 0.999) up to 20 nM
Caco-2 cells: IATEAIENFR = 1.48 fmol/μg, STVVQLLER = 1.17 fmol/μg
Rat enterocytes: IATEAIENFR = 0.75 fmol/μg
STVVQLLER was below quantifiable range in ex vivo samples

These metrics help validate transporter abundance data used in pharmacokinetic modeling.

Applications in Early Drug Development

This platform supports:

Quantitative transporter profiling in human and animal models
Integration with IVIVE models for better prediction of oral drug absorption
Evaluation of cell/tissue models for transporter-dependent drug clearance

The method also complements functional P-gp assays, providing insight into both expression levels and potential efflux capacity.

Download the Poster to Explore Full Methodology

Pharmaron’s platform is designed for teams focused on regulatory-compliant transporter studies. The downloadable poster includes:

Full LC-MS/MS method validation
Sample prep and digestion workflow
Comparative data between cell and tissue models
Surrogate peptide performance metrics

Download the Poster – Gain clarity in transporter expression today.

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