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  1. Advancing Regulatory Science

Effects of Excipients in Generic Drugs Products on Intestinal Drug Transporters

CERSI Collaborators: Kathy Giacomini, PhD, Brian Shoichet, PhD, Deanna Kroetz, PhD (UCSF)

FDA Collaborators: Zhanglin Ni, PhD, Eleftheria Tsakalozou, PhD, Andrew Babiskin, PhD, Liang Zhao, PhD, Susan Zuk, MS, Sruthi King, PhD

Project Start Date: September 2015

Regulatory Science Challenge

Oral drug products such as tablets, capsules and solutions contain the active ingredient (medication) and various other ingredients that are considered to be therapeutically inactive. These inactive ingredients, called excipients, are included in oral products for various reasons, such as to enhance the stability of the active ingredient or change the color or taste. Excipients can differ between brand name and generic products. Although all of the excipients used in oral drug products are approved by FDA, many have not been tested for their ability to affect drug absorption through the intestine. Therefore, laboratory studies are needed to understand the potential differences in excipients contained in brand name versus generic drug products.

Project Description & Goals

The goals of this project are to determine whether excipients interact with intestinal transporters involved in the absorption of various drugs and find the potency of these interactions, with a focus on generic drug products. Approximately 400 excipients will be screened for their potential to inhibit or induce any of the four main intestinal transporters. A list of excipients that interact with transporters and the relevant concentrations will be created and posted on an open-access web-portal developed as part of the UCSF-Stanford CERSI (http://excipients.ucsf.bkslab.orgdisclaimer icon). Ultimately, these studies will help highlight which excipients require special attention in regulatory reviews based on their true inactivity or activity on intestinal transporters and help FDA ensure medication safety and equivalency of generic drugs to brand name products.


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