Bioequivalence and Bioavailability Forum

Dear ioanam!

❝ … conditions of storage of urine samplings

Ones allowing to obtain valid results for long-term stability (i.e., at least from collection of the first clinical sample to closing of the analytical database)…

Whenever possible you should use PP vials instead of glassware.
You should check in analytical method development whether the compound(s) of interest (parent/meta­bolite) bind to the surface of vials (e.g., some tricyclics stick to PP).
Urine samples freeze much faster than plasma / serum / whole blood does; you have to expect many more brocken glass vials of urine samples. If you have to use glass vials, you should allow for more than usual back-ups (and keep them in a plastic box instead of cardboard).