An Overview of Pharmaceutical Excipients: Safe or Not Safe?

A medicine consists of 2 fundamental parts: the active pharmaceutical ingredient and the excipient. Most, if not all, medicines could not be made without the use of excipients. In the early times, the safety of excipients was overlooked and no specific safety tests were generally conducted. This fact has been changed over times and is currently being recognized that the excipient's toxicity is not negligible, because its direct interaction with the active pharmaceutical ingredient or between other excipients may occur, leading to a potential change in the relationship between effectiveness and toxicity. This review is intended to address the general status of the pharmaceutical excipients and to describe the safety assessment. As a summary, this review suggests the interest of simplifying the formulations as much as possible and the interest of reducing the number of excipients necessary to strictly meet the required functions. The risk/benefit ratio of an excipient should be always evaluated on the basis of not only its production and quality but also of its safety. Further research according to Good Manufacturing Practices, Guiding Principles in Toxicology Assessment, Good Laboratory Practices, and Good Distribution Practices requirements are needed and are fundamental for health safety, contributing to a comprehensive picture of this matter.