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Polymyxin impurities and related standards

Polymyxin is held here as a working collection of 38 reference materials across 7 CAS numbers. 9 of the entries are impurity-type materials of the parent, 12 are salt or counter-ion variants and 3 carry a deuterium label. 7 entries carry a verified structure drawing, a coverage of 18%; the rest are listed without a structure rather than with an unverified one. 7 of them sit in tier A or B, meaning the data behind the page is complete enough to be indexed and quoted directly, while 31 remain tier C and are kept for search coverage. Forced degradation on the parent tells you which of these materials a method will actually encounter: hydrolytic stress generates the amide and ester cleavage products, oxidative stress generates the N-oxides and hydroxylated analogues, and photolytic stress generates the ring rearrangements. A standard that is not on that list is usually a process impurity, and it is controlled by the route rather than by the formulation. Where a letter exists in a monograph but not in a supplier catalogue, that gap is what stops a validation study, and it is worth asking for the letter rather than for a percentage.

Sources: DailyMed (US NLM) - NEOMYCIN AND POLYMYXIN B SULFATES AND HYDROCORTISONE OTIC (NEOMYCIN AND POLYMYXIN B SULFATES AND HYDROCORTISON.

7 reference standards related to Polymyxin held in the RSSE catalogue — pharmacopoeial impurities, non-compendial impurities, metabolites and labelled analogues where available.

In this group: 5 fine chemicals · 2 impurity reference standards. CAS numbers are listed for 7 of 7; 7 entries carry a structure drawing.

On this page

7 reference standards

All entries — structure, identifiers and pack sizes

7 reference standards

Frequently asked

How many Polymyxin-related reference standards do you hold?
7 standards are listed on this page as of the latest catalogue build. CAS numbers are published for 7 of them and 7 entries carry a structure drawing. The catalogue is extended as new lots are released.
Can you supply a Polymyxin impurity that is not listed here?
Yes. Non-compendial impurities can be quoted from a structure — a CAS number is not required. Send the structure, a SMILES string or the parent drug substance with your enquiry and we will come back with availability.
What documentation is supplied with Polymyxin impurities?
Every lot ships with its own certificate of analysis. The certificate records the catalogue number, the batch number, the tests performed, the specification applied and the result obtained for that lot. A safety data sheet is supplied with the shipment.
Do you publish prices or a lead time for Polymyxin impurities?
No price list is published: quotations are prepared per enquiry, because availability and packing depend on the lot and the quantity you need. Send the catalogue number and the quantity and a technical contact will answer with availability and a quotation.

Cannot find the impurity you need? Non-compendial impurities can be quoted from a structure — a CAS number is not required. Write to sales@rssechem.com.