Impurity limit

[salfar]

Dear all,

Can anyone tell me how can I define the limit for the summ of all impurities of a drug substance and a drug product? I have searched in the guideline, but I didn't found it...

Thank you in advance,

Sonia

[tom jupille]

No single limit. Depends on the spec for purity of the drug product. If, for example, it's 99%, then the impurities must total <1%. Look something like the USP monographs to give you an idea of what's generally expected.

[Sallybeetle]

The FDA has released a new Impurities draft guidance called "ANDAs: Impurities in Drug Products."

The guidance is derived from the ICH (International Conference on Harmonization) November 2003 guidance "Q3B(R) Impurities in Drug Products."

An article on this appears in the October 2005 issue of Pharmaceutical Technology Magazine.

Hope this helps. I find reading the ICH guidelines very helpful in method and product development work.

[Sallybeetle]

Since I mentioned the FDA and ICH guidance documents in my last post, here are the websites to make your search easier.

FDA Guidance Documents:
http://www.fda.gov/cder/guidance/index.htm

ICH Guidance Documents:
http://www.ich.org/cache/compo/276-254-1.html

Lots of luck in your search. Don't fall asleep at the computer reading all these guidance documents.

[Oliver]

Hi Sallybeetle, thanks a lot for the links they are interesting.