BAC Water

Bacteriostatic Water (USP, BWFI) is a sterile, multi-dose laboratory reconstitution solvent — USP-grade sterile water preserved with 0.9% benzyl alcohol as a bacteriostatic agent. The peer-reviewed literature catalogs bacteriostatic water as the standard solvent for reconstituting lyophilized peptide reference standards in research workflows where multiple withdrawals from a single vial are anticipated. The benzyl alcohol preservative inhibits microbial growth between withdrawals, distinguishing BWFI from non-preserved Sterile Water (USP, SWFI), which is single-use only. Composition is fixed by USP monograph specification: USP-grade sterile water and benzyl alcohol 0.9% w/v. The product supplied here is intended for laboratory reconstitution work only. For research use only; not for human consumption, medical use, or veterinary application. Researchers should reference USP monograph and supplier specifications for context-specific compatibility.

Experimental contexts documented in laboratory practice include reconstitution of lyophilized peptide reference standards for in-vitro and animal-model research, preparation of working stocks for HPLC and mass spectrometry analytical-method development, and as the standard solvent for assay-buffer dilution series where a sterile, bacteriostatic preservative is appropriate. Researchers select between BWFI and non-preserved SWFI based on the downstream assay's sensitivity to benzyl alcohol — most peptide-research workflows tolerate benzyl alcohol at 0.9%, but some cell-culture systems and certain peptide stability assays prefer SWFI. The product is supplied for these and equivalent in-vitro and analytical experimental contexts only, with no associated guidance for human, clinical, or veterinary application. Researchers should consult supplier specifications and assay-specific compatibility documentation when designing context-specific protocols.

Each lot of Bacteriostatic Water (USP, BWFI) is characterized against USP monograph specifications including pH (4.5–7.0), conductivity, total organic carbon, sterility, bacterial endotoxin (LAL assay), and benzyl alcohol content (0.9% w/v target). Sterility is confirmed by USP <71> compendial method or equivalent validated alternative. Bacterial endotoxin is reported in EU/mL on the Certificate of Analysis. Benzyl alcohol content is verified by HPLC or GC analytical method specified on the COA. The COA records the lot identifier, manufacturing date, expiration date, and analytical method versions used, providing a traceable provenance chain from production through release. Researchers requiring batch-level analytical detail should reference the COA distributed with the supplied material rather than rely on category-level summaries.

Store at controlled room temperature (15–30°C / 59–86°F) in the sealed multi-dose vial, away from direct light. The benzyl alcohol preservative permits multiple withdrawals from a single vial when each withdrawal uses a sterile needle and aseptic technique; once the vial is initially accessed, the bacteriostatic shelf-life is typically 28 days at room temperature per USP guidance, after which any remaining solvent should be discarded regardless of vial contents. Do not freeze. Do not use if the solution is discolored, cloudy, or shows particulate matter. Verify the seal integrity before each use. These handling parameters reflect standard USP-monograph practice for bacteriostatic water reference materials and do not constitute preparation guidance for human or veterinary application.