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  1. Advancing Regulatory Science

The Effect of Excipients on the Oral Absorption of Fexofenadine in Humans

CERSI Collaborator: University of California San Francisco: Katherine Yang, PharmD, MPH; Beth Winger, MD/PhD; Anu Patel, PharmD; Maureen Shin, PharmD, MS

FDA Collaborators: Center for Drug Evaluation and Research: Manar Al-Ghabeish, PhD; Minori Kinjo, PhD; Lei Zhang, PhD; Eleftheria Tsakalozou, PhD

Project Start Date: March 1, 2020

Regulatory Science Challenge

Excipients or “inactive ingredients” are added to medicines for many reasons. Excipients help to make medicines more stable so they work better and can also make them taste better. Excipients are meant to be inactive as compared to the “active” ingredient (i.e., the drug substance) which treats the patient’s condition, but they may affect transporters in the gut that are involved in drug absorption. This may change how much of the medicine enters the body. One of those transporters in the gut is called OATP2B1. OAT2B1 can be blocked by several excipients such as sodium laurel sulfate (SLS). SLS blocks the OATP2B1 transporter when tested in the laboratory but the extent to which SLS blocks the OATP2B1 transporter in humans is unclear.

Project Description and Goals

This study will examine how different amounts of SLS in a fexofenadine capsule formulation affect fexofenadine absorption and levels in healthy subjects. Fexofenadine, an over-the-counter allergy medication, is absorbed from the gut through the OATP2B1 transporter. findings of this study may be used by drug manufacturers to develop better drug formulations that reduce or exclude excipients which may interfere with drug absorption in humans.


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