BAC Water

Overview

Bacteriostatic Water for Injection (BWFI) is sterile water containing 0.9% benzyl alcohol as a bacteriostatic preservative. It is the standard reconstitution vehicle for lyophilised (freeze-dried) peptides in research settings. The benzyl alcohol inhibits microbial growth, allowing multi-use of a single vial over a limited period (typically up to 28 days when stored correctly). Unlike sterile water for injection (SWFI), which must be used immediately and discarded, bacteriostatic water supports the multi-dose reconstitution protocols common in laboratory peptide research.

Mechanism of Action

Benzyl alcohol at 0.9% concentration inhibits bacterial proliferation by disrupting cell membrane integrity and interfering with microbial energy metabolism. This concentration is sufficient to prevent growth of most common laboratory contaminants while remaining compatible with peptide stability. The water component serves as the solvent for reconstituting lyophilised peptides, restoring their three-dimensional structure and biological activity. Proper reconstitution technique — slow addition along the vial wall with gentle swirling — preserves peptide integrity by minimising shear stress and foaming.

Research Applications

• Reconstitution of lyophilised peptide preparations
• Multi-dose research protocols requiring preserved diluent
• Peptide stability and solubility studies
• Standard laboratory supply for peptide research workflows