As Safranin O can be prepared in a variety of solvents and at varying concentrations, it is really not possible to give precise guidelines for solution stability.
There is a Safranin O solution that is part of a Gram Stain kit (HT90A). According to the kit Instructions For Use, this solution has 0.6% dye in 20% SD3A reagent alcohol. The expiration date for this solution is 24 months. But if the formulation varies from this exact composition or if other dyes or chemicals are also present, the 24 months expiration dating may or may not be appropriate

