In Vitro Methods to Support Transporter Evaluation in Drug Discovery and Development

Abstract

This white paper addresses current approaches and knowledge gaps concerning methods to assess the role of transport proteins in drug/metabolite disposition in humans. The discussion focuses on in vitro tools to address key questions in drug development, including vesicle-and cell-based systems. How these methods can be used to assess the liability of compounds for transporter-based drug-drug interactions (DDIs) in vivo is also explored. Existing challenges and approaches to examine the involvement of transporters in drug disposition are discussed. This is a PDF file of an unedited peer-reviewed manuscript that has been accepted for publication. NPG is providing this early version of the manuscript as a service to our customers. The manuscript will undergo copyediting, typesetting and a proof review before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers apply.

Key to Opening Kidney for In Vitro–In Vivo Extrapolation Entrance in Health and Disease: Part I: In Vitro Systems and Physiological Data

“…The selection of the most appropriate in vitro system will depend on the question/ hypothesis being investigated and constraints such as cost or availability of fresh human kidney tissue. There is some overlap with in vitro models used to investigate drug transport in the liver, as recently reviewed (31). Variability in transporter kinetic parameters observed between different experimental systems and laboratories and its implications will be addressed in more detail in part II.…”

Quantitative Targeted Proteomics for Membrane Transporter Proteins: Method and Application

“…Nowadays, various in vitro cell culture systems have been used to assess in vitro transporter kinetics for in vivo extrapolation with drug candidates during drug discovery and development (56). For example, plated hepatocytes or cultured hepatocytes between layers of biomatrix are commonly used for in vitro assessment of liver clearance.…”

An Electrically Tight In Vitro Blood–Brain Barrier Model Displays Net Brain-to-Blood Efflux of Substrates for the ABC Transporters, P-gp, Bcrp and Mrp-1

“…The efflux ratios were all above 2, a value, which has been established as a threshold value for demonstrating the presence of active efflux transporters [24]. The applied substrates and inhibitors were chosen to target P-gp, Bcrp and Mrp's.…”

“…However, these studies did not demonstrate vectorial transport, as the endothelial cells were cultured on culture plates. Other studies have demonstrated expression and function of P-gp in the bovine brain endothelial cells [19][20][21], but vectorial transport studies have shown efflux ratios below 2 [19][20][21][22][23], which is the generally accepted threshold for concluding active efflux transporter involvement [24]. However, with the exception of the Cecchelli et al [21], these cell culture models displayed transendothelial electrical resistance (TEER) values in the range of 100-300 Ω·cm 2 [20,22,23], which are relatively low compared to the estimated in vivo barrier TEER of 1,000-2,000 Ω·cm 2 [25,26].…”