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Researcher preparing unlabeled laboratory vials with a precision pipette
Reconstitution · Laboratory protocol

Bacteriostatic Water

Sterile water containing 0.9% benzyl alcohol as a bacteriostatic preservative. A diluent, not a test article.

For laboratory research use only. Material is supplied as a research reference standard and is not approved by Health Canada. Protocols below are compiled from published literature and supplier documentation; they are reference information, not medical advice. Anyone with a health condition or on medication should speak to a physician first.

Before you begin

  • • Lot-matched certificate and laboratory notebook
  • • Calibrated pipettes, low-binding tubes and suitable PPE
  • • Validated solvent, assay reagents and model-specific SOP
  • • Appropriate positive, negative and vehicle controls

Workflow

  1. 1Record the container lot, expiry date and seal condition.
  2. 2Inspect against a bright background; reject cloudy, coloured or particulate-containing solution.
  3. 3Disinfect the closure and allow it to dry completely before each laboratory withdrawal.
  4. 4Run a solvent blank through the chosen analytical method.
  5. 5Label every prepared sample with compound, concentration, solvent, lot, date and operator initials.

Assay design

Run a solvent blank through the analytical method before preparing samples, and include a vehicle-only arm at the matched final concentration in every cell experiment.

Required controls

  • Unopened container inspection
  • Solvent blank
  • Method-specific sterility control
  • Documented lot and expiry

Diluent

Supplied ready to use. Do not dilute further.

Compound-specific: Bacteriostatic water is not the same as sterile water for injection and not the same as saline. The benzyl alcohol is what permits multiple withdrawals from one container; it is also an assay-active compound at sufficient concentration. Where the method requires a preservative-free vehicle, use sterile water instead.

Working range

Carry the benzyl alcohol concentration through your dilution calculation. At low dilution factors it can reach concentrations that affect cell viability, and a vehicle control at matched benzyl-alcohol concentration is the only way to see that.

Run a solvent blank through the analytical method before preparing samples, and include a vehicle-only arm at the matched final concentration in every cell experiment.

Stability

In solution
Use within the period stated on the manufacturer labeling after first entry. Discard if cloudy, coloured or particulate.

Handling notes

  • Inspect against a bright background before every use. Reject cloudy, coloured or particulate-containing solution.
  • Disinfect the closure and let it dry fully before each withdrawal.
  • Record lot and expiry alongside every sample the container was used to prepare.
  • Where a preservative-free vehicle is required by the method, this is the wrong diluent.

Documentation checklist

Record lot and COA, mass balance, solvent and concentration, preparation timestamp, storage history, plate map, replicate plan, instrument settings, exclusions and deviations. Preserve raw data and analysis code with the experiment record.