Sterile water for injection (revision 15)
Old revision·03:31, 11 Apr 2025·AnalyticalAnnie
| Sterile water for injectionDiluent | |
|---|---|
| Composition | Water only; no preservative, no buffer, no tonicity agent |
| Container | Single-entry |
| Contrast with | Bacteriostatic water, preserved |
| Topic infobox · conventions | |
Sterile water for injection is water that has been sterilised and meets compendial requirements for particulates, endotoxin and conductivity, supplied without preservative, buffer or tonicity agent. It is intended for single use in preparing an injection.[1]
Because it contains no preservative, a container that has been entered offers no barrier to growth of organisms introduced at entry, and it is therefore packaged and used as single-entry. This is the operative difference from bacteriostatic water.[2]
It is also hypotonic. Water alone is not isotonic with tissue, so a preparation reconstituted in it is hypotonic unless the solute makes it otherwise, which for a few milligrams of peptide it does not.[1]
Compendial requirements
[edit]The relevant monograph specifies sterility, freedom from pyrogens, limits on conductivity and total organic carbon, and particulate matter limits. It is prepared by distillation or by a purification process of equivalent capability, and it is not simply purified water in a sealed container.[1]
Sterility of the water is not the same as sterility of the preparation made from it. A non-sterile powder reconstituted in sterile water yields a non-sterile solution, and the water's compendial status does not transfer. See Sterility testing.
Endotoxin limits apply to the water because endotoxin survives sterilisation. Water systems are the classic source of endotoxin contamination, and controlling them is a manufacturing rather than a testing exercise.[3]
When it is used rather than a preserved diluent
[edit]Unpreserved water is used where the preparation is for immediate single use, where the active substance is incompatible with the preservative, or where the preservative is contraindicated in the intended recipient.[2]
The trade-off is direct. An unpreserved container must be treated as single-entry, so any material remaining is discarded; a preserved container can be entered repeatedly within its dating. Where a small quantity of active substance is reconstituted into a volume larger than a single withdrawal, that difference determines how much of the material is usable.
For research peptides, compatibility with benzyl alcohol is generally uncharacterised, so neither choice can be justified on compatibility grounds from published data. That is a statement about the evidence rather than a recommendation.[4]
See also
References
- ^ a b c United States Pharmacopeia, monograph Sterile Water for Injection, and General Chapter <1231>, Water for Pharmaceutical Purposes.
- ^ a b United States Pharmacopeia, General Chapter <797>, Pharmaceutical Compounding — Sterile Preparations.
- ^ United States Pharmacopeia, General Chapter <85>, Bacterial Endotoxins Test.
- ^ United States Pharmacopeia, General Chapter <1503>, Quality Attributes of Synthetic Peptide Drug Substances.