Sterilization of Medical Devices
Sterilization of Medical Devices plays a vital role in the overall quality and performance throughout the shelf life.
Recall due to sterility issue… compensations and court cases with customers decrease in the share value… loss of brand image in the market. Sometimes we came across this type of headlines in the news for some well-known companies. what went wrong? How to avoid it for our companies!!
Many medical devices need to be supply in sterile condition and it is the manufacturer’s responsibility to provide assurance about the sterility of the device, till it reaches the intended user. Then how can a manufacturer do it?
Medical Device Sterilization Validation
By following suitable sterilization method and maintaining the packaging integrity, for the specific device.
Ok then, how can we believe that the process followed for the sterilization method give desired sterility levels for each batch? The answer is by validating the process.
Sterilization processes for medical devices, the effectiveness cannot be fully verified by subsequent inspection and testing of each product, we choose to perform Validation. Below are the methods generally used for the sterilization of medical device.
- Steam Sterilization
- Dry-Heat Sterilization
- Gas Sterilization
- Sterilization by Ionizing Radiation
- Sterilization by Filtration
Selecting of a suitable sterilization or medical products method depends on our device material characteristics.
Most of the devices are terminally sterilized by ethylene oxide gas or gamma radiation, as per the device characteristics.
Selection of Sterilization Method
The selection of specific sterilization method and subsequent validation protocol involves the following, but not limited to,
- Evaluation of device materials, components and packaging compatibility with ethylene oxide gas, gamma radiation or other sterilant
- Effects of manufacturing process on device materials
- Desired sterility assurance level
- Impact of sterilization process cycles on the biocompatibility of the finished device
- Applicable Regulations
The sterilization process must be validated for each device to assure that the process is effective enough to meet the desired sterility level and also prove its consistency.
Once the specific sterilization method is selected then the manufacturer should prepare validation protocol for that process, as per the harmonized standards and/or applicable regulations.
The efficacy of any sterilization process for a specific device is evaluated as per the validation protocols and scientific experiments that are designed to demonstrate the sterilization process and its control procedures can consistently deliver a sterile product.
Stages involved in the validation are the following
The sterilization process validation comprises following three stages,
- Installation Qualification (IQ): To demonstrate the sterilization equipment, ancillary equipment and other instrumentation are designed and installed as per their specifications.
- Operational Qualification (OQ): To prove the ability of the equipment to meet the performance requirements as per its design specification.
- Performance Qualification (PQ): During this stage we uses the product to demonstrate that the equipment consistently operated, and the process assures a sterile product as per the specified requirements.
Significance of Sterilization
When there is a requirement to supply a device in sterile state, the manufacturer should have an established sterilized process. That particular process for the specific device must be validated as per the harmonized standards and other applicable standards, accepted by the country regulatory authorities. The sterilization process validation documentation is considered as critical and should be reviewed by the auditors during the CE Marking and US FDA Approval procedures.
We established a sterilization process for our device, and we are following it. Then why can’t we find any issue until we received a complaint from the market? Answer is because, we do not have proper controls on our process and not following the quality management system as per the established procedures.
How can we avoid it?
Sterile Medical Devices Applicable Standards
- EN ISO 11135-1:2007 Sterilization of health care products – Ethylene oxide – Part 1: Requirements for development, validation and routine control of a sterilization process for medical devices
- EN ISO 11137-1:2015 Sterilization of health care products – Radiation – Part 1: Requirements for development, validation and routine control of a sterilization process for medical devices
- EN ISO 11137-2:2015 Sterilization of health care products – Radiation – Part 2: Establishing the sterilization dose.
- EN ISO 17665-1:2006 Sterilization of health care products – Moist heat – Part 1: Requirements for the development, validation and routine control of a sterilization process for medical devices
- AAMI/ISO TIR No.15844 Sterilization of Health Care Products—Radiation Sterilization— Selection of a Sterilization Dose for Single Production Batch
- AAMI/ISO 10993-7 Biological evaluation of medical devices—Part 7: Ethylene oxide sterilization residues
- AAMI/ISO 11737-1 Sterilization of medical devices—Microbiological methods, Part 1: Estimation of population of microorganisms on products
- AAMI/ISO 11737-2 Sterilization of medical devices—Microbiological methods, Part 2: Tests of sterility performed in the validation of a sterilization process