Related substance again

[mfahe]

thanks very much for your response
but i have an a qus. is it a spesific limit for impurity which can i detect in product or material? and if it is how has it been knewn?

[DR]

Generally speaking, in pharma - Any peak that is >0.05 area % vs. API peak is watched on stability studies while anything over 0.1 area % is identified (and also watched).

[PJ8]

Or >0.03 % for a high does compound.

[gbalock]

The ICH Guideline are fairly clear on this (Q3B(R2)). It depends on your maximum daily dose of the drug. There's a great decision chart at the end of this guidance. Here is the link for it. http://www.ich.org/cache/compo/276-254-1.html