BAC Water

BAC Water (Bacteriostatic Water for Injection, USP) is sterile, nonpyrogenic water containing 0.9% benzyl alcohol as a bacteriostatic preservative. In a laboratory research context, it is used as a diluent for the in vitro reconstitution of lyophilized research compounds. It is not a peptide or active pharmacological agent on its own; it is a research-reagent diluent supplied for research use only.

Benzyl alcohol at 0.9% is the preservative specified by the USP monograph for Bacteriostatic Water for Injection. It partitions into bacterial membrane phospholipid bilayers, increasing membrane permeability and disrupting microbial replication. It is broadly active against common environmental contaminants including S. aureus, E. coli, P. aeruginosa, Candida albicans, and Aspergillus niger. It also has a long pharmacopeial history of compatibility with many lyophilized research compounds.

Per the USP monograph labeling, opened multi-dose BAC Water vials should be discarded within 28 days of the first stopper puncture. The benzyl alcohol preservative reliably handles the contamination risk introduced by repeated needle entries across that window. Refrigerated storage at 2-8°C after first puncture is recommended to support preservative performance.

In a research laboratory it is used as a diluent for the in vitro reconstitution of lyophilized research compounds and as a vehicle in subsequent serial dilutions for in vitro assays. It is not appropriate for use in neonatal cell culture systems sensitive to benzyl alcohol, for assays that are confounded by trace alcohol, or for applications where a preservative-free water (Sterile Water for Injection or molecular-biology-grade water) is specifically required. It is not for human or veterinary use.

Sealed vials are stored at controlled room temperature (20-25°C) protected from light. After the first stopper puncture, refrigerate at 2-8°C and discard within 28 days per USP labeling. Do not freeze. Inspect each vial before use for clarity, particulate matter, and stopper integrity.

Bacteriostatic Water for Injection is the standard, pharmacopeially recognized reconstitution diluent for most lyophilized research peptides. Compatibility should always be confirmed against the specific compound's solubility and stability profile - some peptides require acidic, alkaline, or organic co-solvent systems and may be incompatible with benzyl-alcohol-preserved water. Consult the compound-specific COA and reconstitution guidance.