Esterilants

Esterilants are chemical agents used to achieve sterilization of medical devices, instruments, and other reusable items by destroying all microbial life, including bacterial spores, under validated conditions. They are distinguished from disinfectants by their goal of achieving sterility, typically defined by a Sterility Assurance Level of 10^-6. Esterilants can be categorized as gas (or vapor) sterilants or liquid chemical sterilants.

Gas sterilants include ethylene oxide (EtO) gas, which is widely used for complex or heat‑sensitive devices but requires controlled humidity and aeration after processing due to toxic residues. Hydrogen peroxide-based gas plasmas and vaporized hydrogen peroxide (VHP) offer alternatives with shorter aeration times and lower residue concerns. Peracetic acid vapors are another gas‑phase option in some systems, providing sporicidal activity under validated conditions.

Liquid chemical sterilants cover solutions used for immersion or automated processing of heat‑sensitive items. Common systems employ peracetic acid or hydrogen peroxide liquids. Aldehyde liquids such as glutaraldehyde and ortho-phthalaldehyde (OPA) are typically used for high‑level disinfection and, for certain devices and validated cycles, can be part of sterilization processes; however, manufacturers’ guidelines must be followed, as performance can vary by device and cycle.

Process considerations include validated cycles, appropriate device compatibility, and monitoring with chemical indicators and biological indicators to verify sterility. Safety and regulatory aspects address worker exposure, handling and storage, ventilation, waste disposal, and compliance with standards and regulations in health care and manufacturing contexts.