Bacteriostatic Water 10ml | 0.9% Benzyl Alcohol

10 ml of bacteriostatic water in a sealed vial, the standard presentation for reconstituting lyophilised peptides. Water containing 0.9% benzyl alcohol as a bacteriostatic agent.

What is bacteriostatic water?

The difference between bacteriostatic water and plain sterile water is the 0.9% benzyl alcohol. Sterile water is sterile at the moment the seal is broken and offers nothing thereafter. Benzyl alcohol inhibits bacterial growth, which means a vial can be entered more than once over a period without the contents becoming a culture medium.

That is the entire practical distinction, and it is why bacteriostatic water is the default choice for a reconstituted peptide that will be drawn from repeatedly rather than used in a single sitting.

How reconstitution volume sets concentration

The volume you add determines the concentration you end up with, and it is worth doing the arithmetic before opening anything. A 5 mg peptide vial reconstituted with 2 ml gives 2.5 mg/ml. The same 5 mg with 1 ml gives 5 mg/ml. Same peptide, same vial, different working solution.

Add the water slowly, directed down the inside wall of the vial rather than straight onto the lyophilised cake, then swirl gently. Do not shake: agitation shears peptide chains and can leave you with a solution that no longer matches its certificate of analysis.

Storage

Unopened vials keep at room temperature away from light. Once a peptide has been reconstituted with it, the resulting solution follows the peptide's storage requirements, which for most of our range means refrigeration at 2 to 8 °C and protection from light.

How long does bacteriostatic water last?

An unopened vial keeps to the date printed on it, stored at room temperature away from light. Once the stopper has been pierced, the benzyl alcohol continues to inhibit bacterial growth, which is the entire point of the preservative, and a vial in use is conventionally treated as good for around 28 days.

That figure is a handling convention rather than a property of the liquid. The practical limit is usually the number of times the stopper has been entered and how carefully, not the calendar.

Does bacteriostatic water need refrigerating?

No. Unopened or in use, it is stored at room temperature and protected from light. Refrigeration is neither required nor beneficial for the diluent itself.

What does need refrigerating is a reconstituted peptide. Once a lyophilised compound has gone into solution, the resulting liquid follows the peptide's storage requirements, which for most of our range means 2 to 8 °C and protection from light. The water is stable at ambient temperature; what you dissolve into it generally is not.

How much water to add

The volume added sets the concentration, and it is arithmetic worth doing before the seal is broken:

• 5 mg vial + 1 ml water = 5 mg/ml
• 5 mg vial + 2 ml water = 2.5 mg/ml
• 10 mg vial + 2 ml water = 5 mg/ml
• 10 mg vial + 5 ml water = 2 mg/ml

A 10 ml vial therefore covers several reconstitutions at moderate concentration, or a single preparation at low concentration. Add slowly down the inside wall, swirl gently, never shake.

Supplied strictly for laboratory research use only. Not for human or veterinary use, and not for diagnostic or therapeutic application. Purchasers must be 18 or over and are responsible for compliance with the rules applying to them.