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Sterilization Methods

Posted in Medical Device Development

Medical device manufacturers must sterilize medical devices to gain market clearance. Unsterilized instruments and single-use products can transmit infections and cause patient illness or even death. Most germs are invisible to the naked eye, so how do companies sterilize a device and prove that their methods kill harmful bacteria and meet international standards? We’ve outlined basic sterilization methods.

The Standard

International standards regulate medical device production. For example, ISO 13485 validates a company’s quality management system for medical devices. ISO 11137 lays out the requirements for health care product sterilization and disinfection. The sterilization process and sterility testing must be thoroughly documented to demonstrate you’ve met all regulatory requirements.

The Methods

Sterilization removes or destroys microbial life using physical or chemical processes like steam, dry heat, filtration, irradiation, or sterilants to target bacteria, viruses, fungi, and protozoa. Sterilization processes differ based on manufacturers’ recommendations, device classification, design, material density, packaging, and number and type of microorganisms. We’ve outlined some of the most common methods:

  • Wet heat – Also known as autoclaving, wet heat is a steam method that uses an autoclave (a pressurized chamber) to sterilize devices. Pressurized steam heats the material, killing microbes, spores, and viruses. This method is ideal for heat- and moisture-resistant devices like those made of steel.
  • Dry heat – Dry heat involves flaming or baking products in hot air ovens. Since it doesn’t use water, this method is ideal for heat-resistant devices that would be sensitive to moisture, like those made of certain metals or glass.
  • Gas – Most often used for moisture-sensitive devices like electronics, gas methods involve ethylene oxide, nitrogen dioxide, or formaldehyde. These methods attack cellular proteins and the nucleic acids of microorganisms. 
  • Irradiation – Irradiation, or ionizing radiation, uses UV, x-rays, or gamma rays, which penetrate materials and damage DNA. This method detaches electrons from atoms or molecules, effectively destroying microorganisms without leaving behind radioactivity. Irradiation is ideal for heat-sensitive plastics and single-use devices.

The Verification

Manufacturers need to verify that their sterilization techniques are effectively removing biological contaminants without compromising the product. Medical devices can be validated for sterility based on multiple indicators—biological, chemical, and physical reactions. Testing may involve processing microorganisms with a sterilization load and observing bacterial growth over time, using chemicals to observe changes in color or shape, or regulating gauges to ensure certain parameters are met.

Via Biomedical can help you choose the best sterilization and sterility testing to ensure your medical device meets all requirements. We’re ISO 13485 certified, meaning our quality management system will help you create a safe, defect-free product suitable for the market. From product development to packaging, we’ve got you covered. Contact us to learn more.