Product details
Sterile Water for Injection (SWFI) is the preservative-free, single-use reconstitution diluent. The absence of any preservative — the distinction from Bacteriostatic Water — makes it the appropriate choice in two cases: preparations intended for single use within a short window after reconstitution, where multi-use preservation is unnecessary; and peptides whose chemistry or downstream application is incompatible with benzyl alcohol or other preservatives. It is also the diluent of choice where a sterile-filled finished preparation builds its preservation system into the formulation rather than the diluent. It is supplied as a characterized ancillary diluent rather than a research-target molecule.
Peptuno supplies SWFI in sterile vial formats to USP Water for Injection monograph specifications, with sterility, bacterial endotoxin (LAL), and pH documented on the release packet; EP / BP / JP equivalents are available on request. Because there is no preservative, an opened vial has a limited multi-use life (microbial ingress after septum puncture is the limiting factor), so SWFI is matched to single-use or short-window preparation. Match the diluent to the peptide's stability profile: acidic-pH-requiring peptides use the 0.6% acetic-acid diluent; preservative-incompatible peptides use SWFI; preservative-compatible peptides for multi-use can use BAC Water.
Regulatory note: Preservative-free reconstitution diluent for single-use preparations; supplied for Research Use Only. Verify sterility, pyrogen (LAL), and injectable-grade compliance with the destination market's requirements before use.
FAQ
- Why is SWFI the preferred diluent for benzyl-alcohol-incompatible peptides?
- Benzyl alcohol (the preservative in BAC Water) associates with the surface of some short peptides, which can shift solubility, accelerate aggregation, or interfere with benzyl-alcohol-sensitive downstream assays. Preservative-free SWFI removes that concern entirely, at the trade-off that the opened vial must be used within a short window because nothing inhibits microbial growth after septum puncture. For documented benzyl-alcohol-compatible peptides, BAC Water is operationally simpler; for new or untested peptides, SWFI is the conservative default.
- What pharmacopeia specification applies to SWFI?
- Peptuno supplies SWFI to the USP Water for Injection monograph (strict limits for total organic carbon, conductivity, microbial limits, and bacterial endotoxin), with sterility and pH documented on the release packet. International equivalents (EP, BP, JP) are available on request; specify the required monograph at quote stage so the documentation references it.
- How does SWFI differ from the saline and BAC Water diluents in selection?
- SWFI is preservative-free and neutral but unbuffered and non-isotonic, suited to single-use preparation and preservative-incompatible peptides. Saline adds isotonicity (≈ 300 mOsm/L) for physiological compatibility, and BAC Water adds benzyl-alcohol preservation for multi-use vials. The peptide's recommended diluent is noted on its COA; the three cover the common reconstitution cases.
Certificate of Analysis (COA)
The per-lot COA for this product will appear here.
Related products
BAC Water (Bacteriostatic Water for Injection)
0.9% benzyl-alcohol bacteriostatic reconstitution diluent (multi-use)
Saline (0.9% Sodium Chloride Injection)
0.9% isotonic sodium-chloride reconstitution diluent