A Critical Overview of the Biological Effects of Excipients (Part II): Scientific Considerations and Tools for Oral Product Development

It is now recognized that a number of excipients previously considered to be inert have the capacity to alter drug oral bioavailability through a range of in vivo effects. The various mechanisms through which an excipient can affect in vivo gastrointestinal physiology and drug absorption characteristics were explored in A Critical Overview of The Biological Effects of Excipients (Part I): Impact on Gastrointestinal Absorption. The next critical issue that needs to be discussed is how these biological effects are evaluated. Therefore, in Part 2 of this critical overview, the in vitro, in vivo, and in silico methods for evaluating excipient effects are considered. Examples are provided to illustrate how such studies employing these various procedures have been used to promote formulation understanding and optimization. Finally, a discussion of how the Center for Drug Evaluation and Research applies these tools to support biowaivers is provided.

Automated summary

This article discusses how certain excipients can alter drug oral bioavailability through various in vivo mechanisms. The first part explores the impact of excipients on gastrointestinal absorption, while the second part focuses on evaluating these biological effects through in vitro, in vivo, and in silico methods. Examples are provided to illustrate how these studies can be used to optimize formulations. The article also mentions the application of these tools by the Center for Drug Evaluation and Research to support biowaivers.