Principles and Experimental Considerations for In Vitro Transporter Interaction Assays

Abstract

Drug transporters are now universally acknowledged as important determinants of the absorption, distribution, metabolism and excretion of both endogenous and exogenous compounds. Altered transporter function, whether due to genetic polymorphism, DDIs, disease, or environmental factors such as dietary constituents, can result in changes in drug efficacy and/or toxicity due to changes in circulating or tissue levels of either drugs or endogenous substrates.Prediction of whether and to what extent the biological fate of a drug is influenced by drug transporters, therefore, requires in vitro test systems that can accurately predict the risk and magnitude of clinical DDIs. While these in vitro assessments appear simple in theory, practitioners recognize that there are multiple factors that can influence experimental outcomes. A better understanding of these variables, including test compound characteristics, test systems, assay formats, and experimental design will enable clear, actionable steps and translatable outcomes that may avoid unnecessary downstream clinical engagement. This chapter will delineate the role of these variables in improving in vitro assay outcomes.

Predicting transporter mediated drug–drug interactions via static and dynamic physiologically based pharmacokinetic modeling: A comprehensive insight on where we are now and the way forward

“…Also, due to the requirement of regulatory agencies to use the clinical maximum concentration of a test compound in the in vitro inhibition assays, caution should be practiced in terms of the viability and integrity of a transporter cell line, which can get compromised, leading to overestimation of DDI potential. Such aspects can definitely limit the use of in vitro systems, thereby yielding nonreliable data, and hence should be thoroughly evaluated before in vitro system selection (Bhoopathy et al., 2014; Galetin, 2014).…”

“…The overexpressing cell line selected must be easy to transfect using the desired transporter gene, should translate the transporter protein in a sufficient amount, while also showing sensitivity towards the selection marker. Moreover, the data from vesicle systems should be carefully translated to avoid the presence of false transport phenomena that does not occur in vivo (Bhoopathy et al., 2014; Galetin, 2014).…”

“…As should be thoroughly evaluated before in vitro system selection (Bhoopathy et al, 2014;Galetin, 2014).…”

“…The in vitro test systems for transporters can be organ-specific such as Moreover, the data from vesicle systems should be carefully translated to avoid the presence of false transport phenomena that does not occur in vivo (Bhoopathy et al, 2014;Galetin, 2014).…”