Impurities can be introduced during formulation, manufacturing, packaging, or storage. They can compromise product quality, patient safety, and regulatory approval or compliance. If left undetected or uncontrolled, they may trigger costly recalls, delays, and reputational damage. To mitigate these risks, manufacturers should proactively control impurity levels at or below acceptable limits across the product lifecycle by using robust, validated analytical methods and optimizing production to meet patient needs.
To help companies stay ahead, USP provides Impurity Reference Standards for a wide range of drug products. These standards, along with Analytical Reference Materials like USP Pharmaceutical Analytical Impurities and validated methods in USP-NF official Monographs and general chapters, help support robust impurity profiling, ready-to-use analytical methods , and confident product release. USP’s scientific rigor and global recognition provide the foundation for reliable impurity management across the product lifecycle.
USP Impurity Reference Standards are built on a foundation of scientific rigor, undergoing collaborative multi-lab testing, independent expert review, and thorough stability and suitability studies. Continuous monitoring helps ensure reproducibility, accuracy, and ongoing reliability—enabling manufacturers to use the same batch across multiple API or formulation lots with minimal variability and consistent results. Trusted by regulators worldwide, USP standards can help manufacturers reduce risk, save time, and operate with confidence. Rely on USP solutions for impurities to deliver safe, high-quality medicines.
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Pharmaceutical Analytical Impurities (PAI)
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Pharmaceutical Analytical Impurities (PAI)
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Pharmaceutical Analytical Impurities (PAI)
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Pharmaceutical Analytical Impurities (PAI)
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a USP Reference Standard.
Candesartan Cilexetil and Hydrochlorothiazide Tablets
Included excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a USP Reference Standard.
Candesartan Cilexetil and Hydrochlorothiazide Tablets
Included excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Pharmaceutical Analytical Impurities (PAI)
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Pharmaceutical Analytical Impurities (PAI)
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Pharmaceutical Analytical Impurities (PAI)
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Pharmaceutical Analytical Impurities (PAI)
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Pharmaceutical Analytical Impurities (PAI)
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a “USP Reference Standard”.
Pharmaceutical Analytical Impurities (PAI)
Included Excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a USP Reference Standard.
Included excipients
Included General Chapters
Please note that some links below require a USP-NF account to access. “RS” refers to a USP Reference Standard.
Included excipients
Included General Chapters
