Sterile Water for Injection
Preservative-free sterile water reconstitution diluent
Overview
Sterile Water for Injection, catalogued as SWFI, is the unpreserved single-use reconstitution medium for peptides and related sterile injectable preparations. The total absence of any antimicrobial agent is what differentiates SWFI from Bacteriostatic Water, and it makes SWFI the right diluent for two distinct use cases. The first is any preparation that will be used as single-use within a short window post-reconstitution, where multi-use preservation simply is not needed and the preservative would only add unnecessary chemistry to the system. The second is any peptide where benzyl alcohol or other preservatives are chemically incompatible with the peptide or with the downstream application. SWFI is additionally the recommended diluent for sterile-filled finished products whose preservation system is built into the formulation itself rather than the diluent. Vialdyne releases SWFI in 3 ml and 10 ml sterile vial presentations. The release packet documents sterility, LAL endotoxin per USP <85>, and pH against the appropriate pharmacopoeia monograph for the destination market. The selection logic for receiving pharmacies reduces to a three-way branch: peptides that need acidic pH route to the 0.6% Acetic Acid Water option; peptides where preservatives are chemically problematic route to SWFI under single-use prep; preservative-compatible peptides intended for multi-use dispensing route to BAC Water. The correct selection per SKU is documented on the relevant product page and on the released-batch COA.
Who buys this, and why
Custom-blend buyers are almost always OEM clients building a branded product around a specific ratio of two or more peptides. The development workflow is collaborative: ratio target, analytical method to verify it, stability protocol in the chosen carrier, and packaging selection are all defined in the OEM brief before the first commercial run. Sample-stage volumes are usually 5-10 g of finished blend; commercial MOQ depends on the components.
Primary buyer fit: 503A / 503B compounding pharmacies, academic and contract research laboratories, and regional distributors and re-sellers.
Specifications
- CAS
- 7732-18-5
- Purity (HPLC)
- ≥ 99.0%
- Common vial sizes
- 3 ml, 10 ml
- MOQ
- On request
- Lead time
- 7–14 days
- Storage
- Room temperature
Documentation available on request
- Certificate of Analysis (COA)
- Ratio-verification HPLC
- Mass-spec identity of each component
- Stability of the blend (matrix-specific)
- Bacterial endotoxin (LAL, USP <85>)
- Sterile-fill documentation (where applicable)
- SDS / MSDS
- Private-label / OEM specification sheet
Regulatory note
Preservative-free reconstitution diluent for single-use preparations. Verify sterility, pyrogen (LAL), and injectable-grade compliance with target market regulations.
Frequently asked questions
Why is Sterile Water for Injection the preferred diluent for benzyl-alcohol-incompatible peptides?▾
Benzyl alcohol, the 0.9% preservative in BAC Water, interacts with some short peptides through hydrophobic association at the peptide surface. Three operational consequences can follow: shifts in peptide solubility, accelerated aggregation in some cases, and interference with downstream cell-based assays in benzyl-alcohol-sensitive systems. Preservative-free SWFI eliminates this concern entirely, at the trade-off that the reconstituted vial must be used within a short window (typically 24 hours at refrigerated temperature, or single-use immediately) because there is no preservative to hold back microbial growth after septum puncture. For peptides where benzyl-alcohol compatibility is documented, BAC Water remains the operationally simpler choice; for new or untested peptides, SWFI is the conservative default.
What's the production process behind pharmaceutical-grade Sterile Water for Injection?▾
USP-grade Water for Injection is produced through distillation or equivalent purification (reverse osmosis with UF and final-step distillation) from potable feedwater, designed against strict specifications for total organic carbon, conductivity, microbial limits, and bacterial endotoxin (typically less than 0.25 EU/mL). After production, the water is sterilised by autoclave or terminal sterile filtration and filled into sterile vials under controlled cleanroom conditions consistent with EU GMP Annex 1 aseptic-process expectations. The 28-day expiry on opened SWFI vials reflects the absence of preservative, once the rubber septum is pierced, microbial ingress from air or repeated needle introduction becomes the limiting factor. Vialdyne's SWFI ships to USP <1231> Water for Injection monograph specifications; EP, BP, and JP equivalents are available on request for buyers operating into those jurisdictions.
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