What are The Ethylene Oxide Residuals Limits For Medical Devices & Products?
Limited Exposure to Ethylene Oxide (Less Than 24 Hours)
Devices that undergo ethylene oxide (EO) sterilization are placed into one or more of three exposure categories based on the duration of contact a medical device has with a patient. Before you look into exposure categories, determine if your product requires ethylene oxide residuals testing. If your device does require ethylene oxide residuals testing, determine which ethylene oxide extraction method is best for your device, learn how to calculate your ethylene oxide residuals, and find out how to prepare your samples for testing. If you need ways to reduce your ethylene oxide residuals to meet the required limits, please visit our article on key factors that influence EO residuals levels.
The first category and limit you must meet for EO residual testing is limited exposure. ISO 10993 states that limited exposure consists of devices “whose cumulative single, multiple or repeated use or contact” is up to 24 hours. This device category is the broadest. All EO sterilized medical devices must meet the criteria of this category (whether they are in use for less than 24 or more than 24 hours), unless your device falls within one of six special categories.
For limited exposure devices:
- The dose of EO to the patient shall not exceed 4 mg in the first 24 hours.
- The dose of ECH to the patient shall not exceed 9 mg in the first 24 hours.
Prolonged Exposure To Ethylene Oxide (1 Day- 30 Days)
The second category and limit for EO residual testing is prolonged exposure. Prolonged exposure consists of devices “whose cumulative single, multiple, or repeated long-term use or contact” is likely to exceed 24 hours but not likely to exceed 30 days. Limits for limited exposure must also be met for prolonged exposure devices.
For prolonged exposure devices:
- The average daily dose of EO to a patient shall not exceed 2 mg per day. The maximum EO dose shall not exceed 4 mg in the first 24 hours and 60 mg in the first 30 days.
- The average daily dose of ECH to a patient shall not exceed 2 mg per day. The maximum ECH dose shall not exceed 9 mg in the first 24 hours and 60 mg in the first 30 days.
Permanent Exposure To Ethylene Oxide (Lifetime Limit)
The final category and limit for EO residual testing is permanent exposure. Permanent exposure consists of devices “whose cumulative single, multiple or repeated long-term use or contact” exceeds 30 days. Limits for prolonged exposure and limited exposure must also be met for permanent exposure devices.
For permanent exposure devices:
- The average daily dose of EO to a patient shall not exceed 0.1 mg per day. The maximum EO dose shall not exceed 4 mg in the first 24 hours, 60 mg in the first 30 days, and 2.5 g in a lifetime.
- The average daily dose of ECH to a patient shall not exceed 0.4 mg per day. The maximum ECH dose shall not exceed 9 mg in the first 24 hours, 60 mg in the first 30 days, and 10 g in a lifetime.
Ethide Labs is a contract testing organization that specializes in Sterilization Validations and EO Residual Testing. Ethide Labs provides in-vitro cytotoxicity tests in-house and outsources in-vivo cytotoxicity work for toxicity testing of medical devices, products, and drugs. Ethide Labs also offers Microbiology Testing, Bioburden Testing, Environmental Monitoring, Bacterial Endotoxin Testing, Package Integrity Testing & Cytotoxicity Testing services for medical device companies and allied industries. Ethide is an ISO 13485 certified facility.
References
International Organization for Standardization. Biological evaluation of medical devices — Part 7: Ethylene oxide sterilization residuals. Geneva (Switzerland): ISO; 2008. (ISO 10993-7:2008).
