Contract Steam Sterilization

What is steam sterilization?

Moist heat (steam) sterilization is the process of employing saturated steam supplied under vacuum as the sterilizing agent to kill microorganisms on a variety of products in a steam autoclave.

What is steam sterilization used for?

Steam sterilization is commonly used to sterilize many heat-stable, non-porous dry goods as well as liquid products in sealed containers, such as vials, syringes, bottles, and bags that are typically not processed using alternative gas (ethylene oxide or vaporized hydrogen peroxide) or radiation (gamma, electron beam, X-ray) technologies due to material compatibility issues.

Steam sterilization is typically performed in smaller quantities or load sizes and, due to capacity considerations and requirements for thermoresistance, is often considered as a last option when evaluating available sterilization technologies.

How is steam sterilization performed?

The steam sterilization process is performed in a sealed pressure vessel and generally uses both positive and negative pressures throughout the process.

Steam sterilization is a thermal process consisting of three primary process variables: temperature, pressure, and time. The phase change resulting from steam converting to water upon contact with the material being sterilized releases a large amount of energy that denatures cellular DNA and destroys enzymes to kill and inactivate (render incapable of reproducing) microbes.

The sterilant (steam) at or above 115 ºC can penetrate multiple layers of vented sterile barriers such as pouches or thermoformed trays with Tyvek® or medical grade paper venting material.

Moist heat, in the form of steam, can effectively sterilize many complex product design features, achieving sterility assurance levels between 10-3 to 10-6 or better.

What products are commonly processed with steam sterilization?

Examples of products commonly processed with steam include:

• Liquid products in sealed rigid containers
• Glass or polycarbonate syringes
• Glass vials and bottles
• Liquid products in sealed soft containers
• Polypropylene vials and bottles
• Flexible, IV-type bags
• Filters
• Retinal and ocular devices
• Small-volume and custom dental and orthopedic implants
• Wound care products
• Reusable manufacturing components (such as labware, equipment change parts, etc.)
• Various diluents used to reconstitute other products at the point of use
• Other heat-stable and moisture-resistant products

Standards

STERIS complies with the following industry standards and guidance for steam sterilization including ISO 17665 - Sterilization of health care products — Moist heat — Requirements for the development, validation and routine control of a sterilization process for medical devices

STERIS steam sterilization services:

STERIS offers contract steam sterilization services for medical devices, diagnostics, drug delivery systems (absent of active pharmaceutical ingredients), manufacturing components, and more. The contract steam sterilization service is operated from one of our Minneapolis, Minnesota, USA facilities.

Services are provided using dedicated STERIS Finn-Aqua® Biopharma GMP sterilizers qualified in accordance with ISO 17665. On-site TechTeam validation services are available to validate terminal sterilization processes along with an on-site, comprehensive microbiology laboratory for validation and product release testing services (sterility, bioburden, bacterial endotoxin, etc.).

Services offered include:

• R&D testing for early-phase product design and new materials is also routinely provided
• Product compatibility
• Routine bioburden reset processing
• Terminal process validation
• Routine terminal steam sterilization

In addition, various programmable options provide a wide range of process development options. STERIS assists in validating terminal sterilization processes using pulsed air, purge-pulse, steam-air mix (SAMx), air-cool, and forced air process profiles and can accommodate most packaging designs for all classes of devices. STERIS, having installed multiple sterilizers with the same processing capabilities allows for backup and cross-validation capabilities to assure continuous production capacity.

Related content:

TechTalk: TechTalk: Fundamentals of Industrial Steam Sterilization | Video | STERIS AST (steris-ast.com)