Nitrosamine impurities: what a laboratory actually needs on file
· Impurity control · CATO technical documentation
Nitrosamine control has moved from a project to a routine, and routine work is judged on documentation. For each nitrosamine standard in use, the questions that come up in an audit are predictable.
The four documents
- Certificate of analysis, per lot. Not a generic specification sheet. It should name the
catalogue number and the lot number, state the value assigned to the material, and state the analytical basis for that value.
- Safety data sheet. For nitrosamines this is not a formality: it drives the transport
classification, the packing instruction and the labelling on the outer box.
- Identity evidence. A mass spectrum or NMR spectrum that confirms the structure, kept with the
lot record rather than with the marketing file.
- Storage and shipping conditions, in writing. Several nitrosamines are light-sensitive or
volatile, and the storage condition in the catalogue must match the one on the label.
The questions that decide usability
- Is the purity value a measurement or an estimate? A value assigned by qNMR, HPLC or GC is a
measurement and can be defended. A value described as "typical" without a method is not.
- Was the material released against a specification, or simply analysed? The difference matters when
the standard is used for quantification rather than identification.
- What is the lot's retest or expiry date, and what is the basis for it? Stability data or a
convention — the answer changes how long the standard can stay in use.
- Is the salt or free-base form stated? Two nitrosamines that differ only in this respect will not
give the same response.
Practical notes from our own catalogue
We publish the pack sizes, the lead time, the storage condition and the analytical basis for each item on its product page, and the certificate for the lot travels with the shipment. Values marked with a method (HPLC, GC, qNMR) are measured values taken from that certificate; where we have not measured a value, we do not publish one.
For laboratories setting up a method, the useful starting point is the whole set of nitrosamines related to one drug substance rather than a single compound — see our API hubs for the compounds we hold per parent drug.
*CATO manufactures impurity, metabolite and stable isotope-labelled reference standards. Every lot is released with its own certificate of analysis; request a quotation with the catalogue number and the pack size you need.*
Written by CATO. Where a claim depends on an external source we say which one; where it depends on our own catalogue we name the catalogue number so you can check it. Spotted an error? Email chao.lu@cato-chem.com — corrections are published in place.