Webinar Aired: 6/20/2018 Presenter: Joanna Barbara, Ph.D., Sekisui XenoTech Vice President of Scientific Operations Key concepts discussed in this webinar included: - Ramifications of recent FDA in vitro DDI guidance changes to transporter study designs - Challenges from diverse compounds in otherwise straightforward assays - Solutions to problems associated with specific compound characteristics - Case studies of problematic observations or data and the creative methods of troubleshooting applied Synopsis: In vitro drug transporter inhibition and substrate potential assays as well as general cell permeability studies are performed at various stages of drug development to answer myriad questions. They can range from simple permeability screens to kinetic assessments in specialized cell systems using complex assay formats. Drug transporter assays are many and varied because numerous transporter proteins require evaluation, and study designs are usually based around the availability of an appropriate test system to study the transporter protein(s) in question. In general, experiments are conducted using polarized or transfected cell lines, hepatocytes or membrane vesicles. Each test system requires appropriate assay conditions and controls in order to generate useful data. Recent changes to the FDA in vitro DDI guidance document have emphasized the need for more considered transporter study designs to better inform in vivo expectations for drugs in development. The 2017 guidance explicitly recommends consideration of the impact of factors such as stability in the test system, non-specific binding to cells and experimental apparatus and other compound-specific characteristics in study conduct and data interpretation. Since assay designs are limited by individual test system assay needs, practically, this requires study designs to be augmented with careful monitoring and troubleshooting at assay and data interpretation stages when unexpected observations are made. In this webinar, challenges associated with some diverse compounds in what should have been straightforward in vitro transporter assays will be examined. The discussion will focus on cell-based assays and the solutions applied to problems associated with specific compound characteristics, with a progressive analysis of increasingly complex case studies. Case studies will explore the problematic observations or data, creative methods of troubleshooting applied, and how we can learn from those experiences to better understand and address surprises in future transporter studies. Request a copy of the slides or submit questions: https://www.xenotech.com/webinars/challenges-solutions-in-vitro-transporter-research