Sterilants: Definition, Types, Applications, and Safety

A sterilant is a chemical or physical agent that destroys all forms of microbial life, including bacteria, viruses, fungi, and bacterial spores. It achieves sterility (complete absence of viable organisms).

Common Sterilants

Agent	Type	Mechanism	Typical Use
Ethylene Oxide (EtO)	Gas	Alkylates DNA/proteins	Heat-sensitive medical devices
Hydrogen Peroxide (H₂O₂)	Liquid/Gas plasma	Oxidation	Surfaces, instruments, isolators
Glutaraldehyde	Liquid	Cross-links proteins	Endoscopes, heat-sensitive instruments
Chlorine Dioxide (ClO₂)	Gas/Liquid	Oxidation	Water, surfaces, food processing
Peracetic Acid	Liquid	Oxidation	Dialyzers, endoscopes, environmental surfaces
Steam (Autoclave)	Physical	Denaturation by heat/moisture	Heat-stable instruments, liquids
Dry Heat	Physical	Oxidation/denaturation	Glassware, powders, oils
Radiation (Gamma, E-beam)	Physical	DNA damage	Single-use disposables, pharmaceuticals

Safety & Regulations

• Many sterilants are toxic, carcinogenic, or sensitizing (EtO, glutaraldehyde).
• Require proper ventilation, PPE, exposure monitoring.
• Regulated by FDA (medical devices), EPA (environmental), OSHA (workplace).

Key Distinction

Sterilant ≠ Disinfectant. Disinfectants reduce microbes but do not reliably kill spores. Sterilants achieve sterility assurance level (SAL) of 10⁻⁶.