Impurities

When it comes to drug development and manufacturing, impurities can pose very serious risks if undetected or improperly controlled within acceptable limits. Impurities and contaminants discovered during manufacturing can delay product approvals and batch release. Impurities detected in drug products already on consumer shelves can trigger drug recalls and prompt regulatory actions. In a recently released analysis of US FDA reported drug recall data (2012-2023), the most frequent cause of recalls was found to be impurities and contaminants.1

1 Seppe Ghijs et al, “The continuing challenge of drug recalls: Insights from a ten-year FDA data analysis,” Journal of Pharmaceutical and Biomedical Analysis, Oct 2024

Official USP Impurity Reference Standards

Regulatory bodies such as the U.S. FDA and ICH require impurity testing and control to ensure drug safety and efficacy. Failed impurity testing and appearance of degradant impurities in drug products also can indicate a manufacturer’s inadequate understanding of its own production process, limited assessment of potential impurity sources, or poor stability testing practices.

USP Impurity Reference Standards are built on a foundation of rigorous science and developed based on input from a global independent network of scientific experts knowledgeable in R&D, manufacturing, regulations and healthcare.

By using USP Impurity Reference Standards and validated methods in USP-NF monographs and general chapters, you can increase confidence and reduce risk throughout the drug development and manufacturing process, saving time and resources.

Search the USP Store

Quick links

prescription medicine

Standards & solutions in leading generic drug categories

Learn more about USP’s recently released official Reference Standards, monographs and analytical reference materials for impurities in key therapeutic categories:

Standards & Resources for Impurities 

Extractables & Leachables

Regulations require that substances migrating from packaging materials into drug products remain below harmful levels. Extractables & leachable (E&L) impurities linked to pharmaceutical packaging can adversely impact drug potency, stability, safety and quality if not properly analyzed. Find out more about USP’s new Analytical Reference Materials* for rubber oligomer compounds in E&L analytical testing.

Learn more

Short-chain nitrosamines & NDSRIs

Learn more about USP Reference Standards and Pharmaceutical Analytical Impurities* for nitrosamines.

Learn more

Advance method development with USP Pharmaceutical Analytical Impurities

Advance method development with USP Pharmaceutical Analytical Impurities (PAIs)

Lack of available impurity materials can slow down analytical method development, costing time and money and increasing the risk of product release or approval failure. The USP PAI catalog lists more than 700 impurity reference materials including process impurities, degradants and NDSRIs (nitrosamines) and are immediately available for purchase.

*USP PAIs are released using a process developed by our subject matter experts. The release process is based on internal policies, standard operating procedures, and requirements as defined by USP’s Quality Management System.

Access USP’s full PAI catalog

Impurities in High-Risk Excipients

Impurities in High-Risk Excipients

In 2022 and 2023, more than 300 people died from consuming cough syrups and liquid analgesics contaminated with the impurities diethylene and ethylene glycol (DEG and EG). These contamination cases stemmed from limited impurity control in high-risk excipients such as glycerin, propylene glycol and microcrystalline cellulose. USP offers highly-characterized official Reference Standards for excipient impurities.

Search now

General Chapter <477> User-Determined Reporting Thresholds (Official May 2024)

GC <477> provides users with a systematic, risk-based, flexible approach for determining an appropriate numeric value for reporting thresholds for Organic Impurity test procedures in USP-NF monographs.

Access this free webinar to learn more

*USP Pharmaceutical Analytical Impurities (PAIs) and Analytical Reference Materials (ARMs) are different from USP Reference Standards and not required for compendial compliance.