Bacteriostatic Water is a preparation designed solely for parenteral use only after addition of drugs that require dilution or must be dissolved in an aqueous vehicle prior to injection. Bacteriostatic Water is supplied in a multiple-dose container from which repeated withdrawals may be made to dilute or dissolve drugs for injection and the pH is 5.7 (4.5 to 7.0). Water for Injection, USP is chemically designated H2O and the semi-rigid vial is fabricated from a specially formulated polyolefin. It is a copolymer of ethylene and propylene. The safety of the plastic has been confirmed by tests in animals according to USP biological standards for plastic containers.