Sterilization is a validated process used to render medical devices free from viable microorganisms, ensuring patient safety for devices that contact sterile tissue or the vascular system.
Complete Guide to Sterilization
Sterilization is a critical process for medical devices that come into contact with sterile body tissues or the vascular system. It involves validated methods to achieve a defined sterility assurance level (SAL), typically 10โปโถ, meaning the probability of a viable microorganism being present is less than one in a million.
Common sterilization methods:
1. Ethylene Oxide (EtO) Sterilization
- Low-temperature process (37-63ยฐC)
- Suitable for heat-sensitive materials
- Penetrates packaging and device lumens
- Regulated by ISO 11135
- Requires aeration to remove residuals
- Environmental concerns due to emissions
2. Gamma Radiation Sterilization
- Uses Cobalt-60 isotope radiation
- Room temperature process
- Excellent material penetration
- Suitable for sealed, final packages
- Regulated by ISO 11137-1, 11137-2
- Can affect polymer properties
3. E-beam (Electron Beam) Sterilization
- Uses accelerated electrons
- Faster than gamma radiation
- Lower penetration depth
- Regulated by ISO 11137-1, 11137-2
- More precise dose control
- Growing popularity for sustainability
4. Steam Sterilization (Autoclave)
- High temperature (121-134ยฐC) with saturated steam
- Most economical method
- Limited to heat-stable materials
- Regulated by ISO 17665
- Common for reusable surgical instruments
- Short cycle times
Sterility Assurance Level (SAL):
The probability of a single viable microorganism occurring on a product after sterilization:
- SAL 10โปโถ - Standard for most medical devices
- SAL 10โปยณ - Low-temperature sterilization, some Class I devices
Validation requirements:
Manufacturers must demonstrate:
- Installation Qualification (IQ)
- Operational Qualification (OQ)
- Performance Qualification (PQ)
- Routine monitoring and revalidation
- Bioburden testing before sterilization
- Sterility testing after sterilization
Key standards:
- ISO 11135 - EtO sterilization
- ISO 11137 (parts 1-3) - Radiation sterilization
- ISO 17665 (parts 1-3) - Steam sterilization
- ISO 11138 - Biological indicators
- ISO 11737 - Microbiological methods
Regulatory considerations:
- Must be validated according to ISO standards
- Part of Quality Management System (ISO 13485)
- Included in Design History File (DHF)
- Critical for Class II and III sterile devices
- Requires stability testing post-sterilization
Related Terms
More Compliance & Standards
View allThe FDA's Quality System Regulation (QSR) that establishes current Good Manufacturing Practice (cGMP) requirements for medical device manufacturers in the United States.
A systematic, independent examination of a Quality Management System to determine whether quality activities and results comply with planned arrangements and whether these arrangements are implemented effectively.
A systematic approach to investigating, correcting, and preventing quality problems in medical device manufacturing and operations.
A mandatory conformity marking for medical devices sold in the European Economic Area, indicating compliance with EU health, safety, and environmental requirements.
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