Now we have to perform some research activity for determination of stability for standard, sample and system suitability solutions(resolution solution).What formal requirements or acceptance criteria are there for determination of solution’s stability.
There are none! This subject is not even covered in ICH Q2(r1). However, for the API the acceptance criteria is the specification range and a %RSD of NMT 2.0%. Thus, the assay of the standard and sample solutions are compared to a ‘freshly’ made API working solution.
Don’t forget the mobile phase too! As the mobile phase ages the organic will evaporate and RP retention times will lengthen.