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Impurity Reference Standards

Pharmacopoeial impurities, nitrosamines, metabolites, labelled internal standards and API working standards, each backed by analytical data for method development and QC.
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Impurity Reference Standards is the largest division in the catalogue. It holds named EP and USP impurities, process-related and degradation impurities, nitrosamine drug substance related impurities, metabolites, deuterated and 13C labelled internal standards, and working standards of the parent APIs. Analysts use them to identify peaks, validate related-substance methods, set response factors and run routine release testing.

Choosing a standard comes down to identity, purity and documentation. Each listing gives the structure, molecular formula and CAS number where one exists. The data package normally includes HPLC purity with NMR, MS and IR as relevant to the compound, and some items also carry TGA or water content. Quantities are typically 10 mg to 100 mg, with larger amounts on request.

When an impurity is not listed, our chemists can synthesise and characterise it against your structure. Standards are packed in amber vials, sealed against moisture and sent by express courier. Browse by API on the impurity standards index to see every related compound for a drug in one place.

Impurity Reference Standards: questions buyers ask

How is the purity of an impurity standard determined?
Purity is usually assigned by HPLC area percentage, supported by structural confirmation from NMR and mass spectrometry. Where needed, water content, residual solvents or a mass balance approach are added. The methods used and the results for your lot are listed on the certificate of analysis that comes with the vial.
Can I use your impurity standards in place of official pharmacopoeial references?
Our standards are secondary or research materials, not official pharmacopoeial references. Many laboratories use them for method development, peak identification and routine testing, and keep official references for disputes or regulatory submissions where these are mandated. Your quality system and regulator decide which reference is acceptable for each test.
How long does custom synthesis of an unlisted impurity take?
Timing depends on the route, the number of steps and how hard the compound is to isolate. Simple derivatives may be ready within a few weeks, while multi-step or unstable targets take longer. Send the structure or name through the quote panel and we will return an estimate together with the planned characterisation package.

Have a list of compounds to price?

Paste up to 200 CAS numbers into Bulk CAS lookup, or send one enquiry for everything in your quote list. We reply with price, lead time and documents.

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