P-glycoprotein Membrane Transporter: Accurate Quantification

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.

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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