Frequently Asked Questions About Ethylene Oxide Sterilization
Q: What is an ethylene oxide sterilizer?
An ethylene oxide (EtO) sterilizer uses ethylene oxide gas to sterilize medical devices and other items that cannot be sterilized by heat or steam. Ethylene oxide is a powerful disinfectant that effectively kills microorganisms such as bacteria, viruses, and spores. It is particularly suitable for sterilizing heat- and moisture-sensitive items, such as certain medical devices, plastics, and precision instruments.
Q: What products are suitable for ethylene oxide sterilization?
A: Ethylene oxide is widely used in medical and industrial sterilization. It is commonly used for gas fumigation sterilization of food, textiles, and other heat-labile pharmaceuticals that cannot be sterilized by other methods, as well as surgical instruments, leather, cotton, synthetic fabrics, precision instruments, biological products, paper, books, documents, certain pharmaceuticals, and rubber products. In the medical industry, it is widely used for medical devices made of plastic, metal, and non-woven fabrics, such as infusion sets, syringes, biopsy forceps, medical catheters, surgical gowns, masks, and surgical forceps.
Q: Can my product be sterilized immediately after leaving the factory?
A: No. The sterilization effectiveness of ethylene oxide cannot be determined through post-sterilization testing. It is a specialized process that requires strict control throughout the entire sterilization process. This control requires careful sterilization parameter design and can only be achieved after confirming that the sterilization effect meets the requirements. If a sterilization process that has not been validated is used haphazardly, sterilization may not be achieved, resulting in the product being contaminated with bacteria, which could lead to bacterial infection in patients, or even multiple patients. Therefore, laws and regulations in various countries require sterilization confirmation before sterilization.
Q: What exactly is sterilization confirmation?
Simply put, to achieve the desired sterilization effect, a sterilization process and process parameters for each step are designed. After multiple tests of the designed process and parameters, reliable sterilization process parameters are obtained to ensure sterilization effectiveness. This process is called sterilization confirmation. Through these tests, we can: 1. confirm that the product's sterility assurance level meets the desired target; 2. determine the sterilization process parameters for routine sterilization and establish standardized sterilization operation documentation and control requirements.
Q: Sterilization is performed by the sterilization service provider, so why should the product manufacturer bear the responsibility for sterilization confirmation?
A: Providing qualified products that meet regulatory requirements is the responsibility of the medical device manufacturer, or the company that lists the product on the list. As the competent authority, only the medical device manufacturer can be held accountable. Of course, medical device manufacturers can transfer some of this responsibility to the sterilization service provider through an agreement, but this is merely a transfer of responsibility; the manufacturer still bears the responsibility.
Q: I'm not sure what size sterilizer to choose.
A: This depends primarily on the customer's sterilization volume and lead time. For example, if you produce approximately 10 cubic meters of goods per day, a 15 cubic meter cabinet is generally sufficient. The actual sterilization volume is generally around 70% of the cabinet size. However, during validation, it is recommended to validate a larger cabinet, such as a 30 cubic meter cabinet. This serves as an alternative and, if lead time is sufficient, the sterilization cost of a larger cabinet can be reduced.
Q: What is the sterility assurance level? Can I pass the sterility test on a product directly after routine sterilization?
The sterility assurance level refers to the probability of detecting viable microorganisms on a unit product after sterilization. It is usually 10-6 or 10-3 (when this value is used for the sterility assurance level, the value of 10-6 is less than 10-3, but the sterility assurance level is higher than 10-3). The so-called 10-6 means that the probability of viable microorganisms on the product is 10-6. Through risk analysis, medical device sterilization experts from various countries believe that the probability of viable microorganisms on the product must reach 10-6 to be safe. So can 10-6 be achieved through product testing? Let's assume that a sterilization batch is 100 boxes, each box contains 100 products, which means that a sterilization batch is 10,000 products. We checked the GB2828 standard and found that its AQL upper limit is 0.01. This means that the sampling control method can only guarantee a quality level of one in ten thousand, and the requirement of 10-6 cannot be detected at all. Even at the level of 0.01, the number of test samples required is 1250 [0 1]. This means that 1,250 products must be sampled, all of which must be sterile, to determine that the 10,000 products meet the acceptable level of 0.01. How much does this cost? What are the risks? It's important to understand that the false positive rate for sterility testing is approximately 1 in 100. This means it's impossible to verify the sterility of a batch of products by testing sterilized products. This is both theoretically impossible and practically impossible.
Q: As a manufacturer of ethylene oxide sterilizers, can Riche sterilize my products directly?
A: No. First, although the products are similar, the production environments (including the production workshop environment, water, equipment, and operators) vary, potentially carrying different microbial populations. Using unverified sterilization parameters for sterilization may not guarantee sterility. Second, we conduct sterilization confirmation for each customer's product, develop specific sterilization parameters, and generate a report upon completion of the sterilization confirmation. The sterilization confirmation report details the product range covered, including product name, model specifications, initial packaging structure, materials, outer box material, dimensions, and other details (including photos), as well as detailed raw data and analysis results from the sterilization confirmation. Due to confidentiality agreements, this report is for the exclusive use of this client and cannot be shared with any other clients. Therefore, if your company does not perform sterilization confirmation, you will not be able to obtain the sterilization confirmation report, which in turn means you will not be able to obtain your sterilization parameters (which are official documents and are based on the sterilization confirmation), making routine sterilization impossible. If interested, please contact us online and our professional technicians will be able to answer your questions.
Q: How long does sterilization confirmation take?
A: At least 45 days. For the initial sterilization confirmation, we typically run seven cycles: four half-cycles, one short cycle, and two full cycles. Each half-cycle and short cycle requires a 48-hour pre-cooling period to ensure the product is cooled to 0°C, followed by approximately 24 hours of pretreatment, sterilization, and analysis. Including BI preparation, the sensor takes approximately four days to complete one cycle, and approximately 28 days to complete seven cycles. This, combined with the time required for testing and report generation, suggests that 45 days is a relatively short timeframe. Furthermore, if a sterilization cycle deviates or the expected results are not achieved, parameters must be readjusted and the sterilization cycle must be rerun. Furthermore, the sterilizer also has routine sterilization tasks, so the actual validation time may exceed 45 days. Typically, it takes 60 to 90 days. Sterilization validation is a complex laboratory process, and complex products often require even longer validation time.
Q: How much can a 15-cubic-meter sterilizer sterilize at a time?
A: During sterilization, we place the product on pallets, which measure 1.2 meters (length) x 1 meter (width) x 2.2 meters (height). We have four pallets. Depending on your company's container and pallet combination, we can typically hold 10 to 11 cubic meters of cargo. A 30-cubic-meter autoclave can typically hold 20 to 22 cubic meters of cargo.
Q: Our product is packaged in plastic (PE film). Can it be sterilized?
A: According to ISO 11135, products packaged in plastic bags are not permitted to be sterilized with ethylene oxide. Paper-plastic dialysis bags are recommended for packaging. However, there are currently no clear regulations in my country or other countries regarding this. Therefore, in practice, products packaged in plastic bags are still sterilized with ethylene oxide, but the sterilization parameters require specific settings. Furthermore, analysis of products packaged in plastic bags is very difficult, typically requiring more than ten days or even longer.
We recommend using packaging materials with dissolving properties.
Q: Our product is not heat-resistant. Can it be sterilized with ethylene oxide?
A: Our sterilization parameters generally range from 25°C to 65°C. We recommend that materials, packaging materials, and excipients used in the production process and in specialized processes have a temperature resistance exceeding 60°C to avoid damage to the product. If there are specific temperature resistance requirements, low-temperature sterilization requires specialized validation.
Q: After ethylene oxide sterilization, some of our products are experiencing peeling or deformation (such as bending or cornering) at the bonded areas. What's going on?
A: Ethylene oxide sterilization requires a specific temperature, generally around 54°C. However, some products have poor temperature tolerance, and temperatures exceeding 50°C may degrade the product's physical properties. This, combined with a reduction in bond strength, can lead to the aforementioned phenomenon.
Therefore, sterilization validation of the product is crucial. Confirming the appropriate sterilization method and parameters for the product is crucial. This ensures that the product, under these sterilization conditions, not only meets the sterility assurance level for sterilization but also maintains the intended properties after sterilization.
Q: Do samples for bioburden testing need to be produced in a cleanroom?
A: Samples used for bioburden testing must be produced using the same production process as for routine sterilization. The remaining test samples should be produced using the same process as for routine sterilization.
Q: What is the purpose of the short sterilization validation cycle?
A: The short sterilization validation cycle is used to assess the compatibility between IPCDs, EPCDs, and products. Through a short cycle, EPCD resistance must be ≥ IPCD resistance ≥ product resistance. The product must undergo full sterility testing (preferably according to pharmacopoeial requirements).
Q: What is the purpose of a full-cycle sterilization confirmation procedure?
A: The full cycle sets an upper limit for sterilization process parameters, thus challenging the physical and chemical properties of the product (including sterilant residues). Specifically, samples are sterilized again, i.e., secondary sterilization. This is to test the reliability of secondary sterilization. The full-cycle product performance testing items, quantity, and methods are entirely up to the customer; we do not set any requirements. We have a gas chromatograph for EO/ECH testing and can perform these tests, but we do not have laboratory certification. If a customer requires this, they should outsource it to a qualified testing agency. Please note that EO/ECH testing has a time limit. If outsourced, the product must be frozen on dry ice before shipping. The laboratory should also keep the package on dry ice after opening it.
Q: Do products sterilized routinely require EO/ECH residue testing?
A: Uncertain. According to ISO standards and practices, EO/ECH residue testing is generally not required. As long as the residual content is confirmed according to ISO 10993-7 for release, routine sterilization processes can also be analyzed according to the standard. However, currently, the release of sterile products in my country must not only consider the requirements of ISO 10993-7 but also meet the requirements of product registration standards. Product registration standards are established when companies apply for product registration certificates with the China Food and Drug Administration. It should be noted that many companies do not fully consider the issue of residual content when establishing product registration standards, instead following the old practice of requiring EO/ECH residue content as a batch inspection item. Since companies require batch-by-batch testing for EO/ECH residue content, they have no choice but to follow this practice.
Q: How long can my product be stored after ethylene oxide sterilization?
A: Ethylene oxide sterilization is a process that kills bacteria. After sterilization, if the environment remains sterile, the product will remain sterile for a long time, as long as the environment remains unchanged. In fact, the sterile life of the product after sterilization has little to do with the ethylene oxide sterilization process. The sterile life cycle is maintained by the initial packaging of the product (also known as sterile packaging or sterile barrier).
