How to determine mobile phase expiration for FDA filing.

[JamesP]

The FDA is requiring us to set expiration dates for our mobile phases. We are allowed to present relevant literature searches as justification for setting expiration dates. Where would I begin to look to generate these relevant literature searches? We use water/acetonitrile mobile phases with various buffers. Thank you.

Jim

[Consumer Products Guy]

All the searching likely won't help much. Do your own study, document that results/system suitability are not affected after a certain number of days.

I'll tell you right now: our company doesn't address such longevity in our cGMP test methods, only the calibration standard "lifetime".

[michaelcarolus]

Hi JamesP

We generally do mobile phase shelf life when we do our method validation. We run our system suitability stds on day 1 , during the validation and then at the end of the validation e.g. after 10days. If the system suitability passes after day 10 then we have a shelf life of 10 days. We also look for any visible signs of precipitation or cloudiness of the mob phase. I hope this helps.

Regards
Mike

[DR]

We rely on internal SOPs that assign a month to many solutions that contain at least 5% of an organic solvent, a week for buffers. Of course, these dates presume that there are no signs of life in the solutions.

[mattmullaney]

Hi JamesP,

My experience at three different jobs is, overall, quite similar to michaelcarolus' and DR's. Eluent "stability" based upon chromatographic performance (successful attainment of system suitability) was/is established in pre-validation/validation over ca. a week's time or so. Eluents are observed for precipitation, buffer pH studied (aqueous only), occasionally titrations to observe loss of volatile eluent additives are sometimes conducted...these types of things...where the eluent(s) are stored under "normal conditions", which would depend on the nature of the mixtures/solvents involved.

I don't know that you'll have much good fortune in searching for the data for which you are seeking...these kinds of things tend to be "in-house" only...how to define a "standard" set of conditions for "eluent stability" when so many eluents can be made/stored in so many different ways? Not at all like EI data for GC-MS where there is a standard potential where the analytes are ionized, so-to-speak.

[JamesP]

Thank you Michael, Matt and DR. I assumed an in house validation was necessary given the nature of the question. I won't invest any time in a literature search. We'll just do the validation over a couple weeks. Thank you again for your input.

Jim