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Ruggedness - Quick Response Requested

All,

When validating an HPLC impurity method, is there an industry standard for acceptance criteria of agreement between two analysts?

We typically use NMT +/- 10%, but this is based on a peak with good response. I am currently working with a method that I’m not at liberty to change at this point and my impurity has a very low peak area (~800-1000).

My concern is that any difference will be greatly magnified at this level. Is it reasonable/acceptable to widen my acceptance criteria to 20% or even 25% agreement between two analysts?

I thank you in advance for a quick response. Deadlines are looming…

Jeff

Dear Jeff
All in all it depends on the proposed limit on the basis of peak response, For an impurity method, results obtained in multiple laboratories will be statistically equivalent or the mean results will be within 10% (relative) of the value obtained by the primary testing lab for impurities, If Impurity limit is from 0.1-1.0 % then criteria would be within 25% and it can be within 50% for impurities limit less than 0.1%.

[quote=Shahid Ali]Dear Jeff
All in all it depends on the proposed limit on the basis of peak response, For an impurity method, results obtained in multiple laboratories will be statistically equivalent or the mean results will be within 10% (relative) of the value obtained by the primary testing lab for impurities, If Impurity limit is from 0.1-1.0 % then criteria would be within 25% and it can be within 50% for impurities limit less than 0.1%.[/quote]

Nice post Shahid