Bioequivalence and Bioavailability Forum

Hi everyone,

I would just like to know, what is your experience/understanding regarding stability of stock and working solutions.

According to the new EMA guideline: "It is not needed to study the stability at each conc. level of working solutions and a bracketing approach can be used".

We used to deal with this situation in two ways:
1. If working solutions were prepared in the same solvent as the stock solution, we performed stability experiments only for stock solution (i.e. bench-top for X hours and refrigerated/frozen for Y days).
2. If working solutions were prepared in different solvent than the stock solution, we also performed stability experiments for working solution but only at the highest concentration of working solution.

Now it seems that EMA would like the stability to be assessed also at lowest concentration of WS....

Any other opinions/suggestions would be appreciated.

Regards,
Marko