Answers to the most common questions about pharmaceutical impurity standards, reference standards, CoA, nitrosamines, ordering and pan-India delivery.
Below are answers to the questions QC labs, R&D teams and procurement teams ask us most often about pharmaceutical impurity standards. If your question is not covered, contact us or call +91 78764 82601.
An impurity standard (impurity reference standard) is a highly characterised sample of a specific impurity of a drug substance, for example a process by-product, a degradation product or a nitrosamine. Laboratories use it to identify the impurity in chromatograms and to measure how much of it is present in an API or finished product.
A reference standard is any well-characterised material used as a benchmark in testing. It can be the API itself or an impurity. An impurity standard is a type of reference standard that represents one specific impurity. Labs typically use both: the API reference standard for assay and the impurity standards for related-substances testing.
Primary standards are issued by pharmacopoeial bodies. In India, Indian Pharmacopoeia Reference Standards (IPRS) are issued by the Indian Pharmacopoeia Commission (IPC). They are authoritative but limited in availability and often expensive. Secondary or working standards are characterised materials that labs use for routine testing; they are qualified against a primary standard where one exists. For many impurities no pharmacopoeial standard exists at all, so a well-characterised impurity standard with a full CoA is the practical choice.
Our catalogue covers process-related impurities, degradation products, nitrosamine impurities (including NDMA and NDEA), metabolites, stable isotope-labelled compounds (deuterated, 13C and 15N) and research chemicals for 2,700+ parent drugs. You can browse by drug name in our product catalogue.
Regulators expect impurities in drug substances and drug products to be identified, reported and controlled within defined limits. Impurity standards make this possible: they confirm peak identity, allow accurate quantification, and are needed for method development, method validation, stability studies and batch release testing.
Use the search box on the Products page. You can search by impurity name, parent drug name or CAS number. You can also filter the catalogue by first letter (A-Z) or choose a parent drug from the category dropdown.
Yes. Type the CAS number (for example 62-75-9 for NDMA) into the product search box and matching products will be shown.
Yes. We offer custom synthesis of impurities, metabolites and reference materials that are not listed. Send us the structure, name or CAS number, the quantity and the purity you need through our contact form, and we will reply with feasibility and a quotation.
Yes. We supply deuterated (d3, d4, d6 and more), 13C and 15N labelled compounds, which are used as internal standards in LC-MS/MS and GC-MS methods. See our isotope-labelled compounds.
Yes, including NDMA, NDEA, other small-molecule nitrosamines and their deuterated internal standards. Browse our nitrosamine impurities or read our guide to nitrosamine impurities.
Yes. Every product is supplied with a Certificate of Analysis. A CoA typically includes the chemical name, structure, CAS number, molecular formula and weight, batch number, appearance, identity data (such as NMR and mass spectrometry), chromatographic purity (HPLC or GC), storage conditions and retest date. Read what an impurity standard CoA should contain.
We are GMP certified and follow an ISO 9001:2015 quality management system. More details are on our Quality page.
Purity depends on the compound and is reported batch-wise on the CoA. Impurity standards are supplied at high chromatographic purity suitable for identification and quantification. If your method needs a minimum purity, mention it in your enquiry and we will confirm before you order.
Yes. Characterisation data such as 1H NMR, mass spectrum and HPLC chromatogram can be shared along with the CoA. Let us know your documentation requirements when you request a quote.
Not necessarily. In HPLC the salt or free-base form does not change how the impurity behaves in the mobile phase, so either form can be used to identify the peak. For quantification, correct for the molecular weight difference between the salt and the free base (or use the potency stated on the CoA).
Prices depend on the compound, quantity, purity and documentation required, and custom compounds are quoted individually. Add products to your enquiry cart or use the contact form, and we will send you a quotation, usually within 24 hours.
Impurity standards are normally supplied in milligram-scale packs for analytical use. Larger quantities can be arranged for many compounds, especially through custom synthesis. Mention the quantity you need in your enquiry.
Yes. We deliver across India, including the major pharma hubs in Himachal Pradesh (Baddi), Punjab, Haryana, Delhi NCR, Gujarat, Maharashtra, Telangana, Andhra Pradesh, Karnataka and Tamil Nadu. Materials are packed with pharma-grade packaging, and cold-chain packing is used where the product requires it.
Yes. We are a GST-registered business and provide a GST invoice with every order.
Follow the storage condition printed on the label and the CoA. Many impurity standards are stored refrigerated (2-8 °C) or frozen, protected from light and moisture. Let the container reach room temperature before opening to avoid condensation, and close it tightly after use.
Process-related impurities come from manufacturing: starting materials, intermediates, by-products, reagents and catalysts. Degradation products form when the drug breaks down during storage or because of heat, light, moisture, oxidation or interaction with excipients. Read more in What are pharmaceutical impurities?
For a drug substance with a maximum daily dose of up to 2 g, the ICH Q3A guideline sets a reporting threshold of 0.05%, an identification threshold of 0.10% (or 1.0 mg per day, whichever is lower) and a qualification threshold of 0.15% (or 1.0 mg per day, whichever is lower). Above 2 g per day the thresholds are lower.
RRF compares the detector response of an impurity with that of the API at the same concentration. If the impurity responds differently, its percentage calculated from peak area alone will be wrong. Determining the RRF needs a pure impurity standard. See how impurity standards are used in HPLC and LC-MS.
Usually you need standards for every specified impurity in your specification (known process impurities and degradation products). They are used to prove specificity, determine LOD/LOQ, establish linearity and accuracy at the specification level, and calculate RRFs. Share your specification or pharmacopoeial monograph and we will help you identify the standards required.
The internationally published acceptable intake (AI) limits are 96 ng/day for NDMA and 26.5 ng/day for NDEA. Nitrosamine drug substance-related impurities (NDSRIs) are assigned limits based on their predicted carcinogenic potency. Always check the latest requirements of the regulator you file with.