Sterile Technique & Storage Basics
USP <797>-informed handling: diluents, beyond-use dates, cold chain, and the contamination pathways that ruin vials.
Diluents and the 28-day convention
Bacteriostatic water is sterile water plus 0.9% benzyl alcohol, which suppresses bacterial growth across repeated punctures — the basis of the common 28-day multi-dose window. Preservative-free sterile water is single-use. Neonates must never receive benzyl alcohol, and the pharmacy label always overrides conventions.
Handling that protects the vial
- Wipe the septum with a fresh alcohol swab and let it dry before every puncture.
- One sterile syringe per puncture; never return used needles to a vial.
- Inject diluent down the vial wall and swirl gently — shaking shears fragile peptide bonds without visible warning.
- Refrigerate reconstituted vials, label with date and concentration, and discard on the beyond-use date or at any cloudiness or particles.
Lyophilized vs reconstituted
Freeze-dried powder is relatively stable; solution is where degradation clocks start. Heat, light, agitation, and repeated septum punctures all accelerate loss of potency — and a degraded vial usually looks identical to a good one.
Knowledge check
Answer 5 questions — 4 correct passes and earns 50 points.
1. What distinguishes bacteriostatic water from sterile water for injection?
2. The common maximum window for a punctured bacteriostatic water vial is:
3. Why swirl rather than shake a reconstituting peptide vial?
4. Which patient group must never receive benzyl alcohol?
5. A refrigerated reconstituted vial two weeks old looks slightly cloudy. You should:
Points are credited once per module, up to 5 point-earning completions per calendar month. Back to all modules