Wouldn't it be interesting if we had this item in game.
For the guys who don't know what the white phial is: the white phial is a legendary item, when you fill it with a potion and consume it, the phial will replenish itself allowing for infinite use.
Of course the phial would allow only 1 type of potion to be stored, with the ability to change it at the cost of discarding the other.
In my opinion, the phial should have a questline, or for the people who don't have the time to do it, there could be an option to buy it from crown store.