Reply to Karl I’m really certain it remains only considered a total of 5mg you've in a single vial. Working with expired bacteriostatic water is not really recommended as it might not be efficient or safe. The expiration date suggests the time period through which the item is guaranteed via https://bacteriostatic-water-0-946789.tribunablog.com/detailed-notes-on-30ml-bacteriostatic-water-47771417