Butterworth has assisted clients in controlling ethylene oxide (EO) and its corresponding hydrolysis products, ethylene chlorohydrin (ECH) and ethylene glycol (EG), in accordance with ISO 10993-7:2022 for an extensive range of medical devices and packaging materials, including process development. Sterilisation using EO gas is used for articles made of plastics that cannot tolerate the higher temperatures required by simpler, cheaper procedures, such as autoclaving. EO is also used for the sterilisation of other items such as surgical fabric dressings and operating theatre drapes.
ISO 10993-7:2022
This standard categorises devices into three exposure categories:
- Category A -Limited Exposure: devices whose cumulative sum of single, multiple or repeated contact is up to 24 hours.
- Category B -Prolonged Exposure: devices whose cumulative sum of single, multiple or repeated contact is likely to exceed 24 hours but not 30 days.
- Category C -Permanent Contact: devices whose cumulative sum of single, multiple or repeated contact exceeds 30 days.
It also specifies the maximum levels of release of EO and ECH residues over specific time periods for each device category.
Two types of residue extraction from samples before analysis are defined:
- Simulated-Use
- Exhaustive
Care needs to be taken when assessing which option to choose for a specific medical device. Simulated use is based on water extraction to evaluate the residue levels actually available to a patient or device user during routine use and is mainly applicable to categories (A) and (B). Exhaustive extraction is defined slightly differently in that the definition states: extraction until the amount of EO or ECH in a subsequent extraction is less than 10% of that detected in the first extraction, or until there is no analytically significant increase in the cumulative residue levels detected. It typically can be applied to category (C) devices. The ISO reference procedure is Simulated-Use extraction.
Why use Butterworth Laboratories?
Butterworth has highly motivated staff and previous experience in this analysis, developed over many years. We can also offer expert advice on sampling and sample transport, both of which are vital to achieving accurate results and regulatory approval.
Frequently asked questions
Yes. Analytical data generated can support regulatory submissions, quality investigations, supplier qualification, and ongoing stability programmes.
By identifying the level and time required for de-gassing EO after sterilisation, this part of the process can be streamlined.
Yes. Butterworth has experience developing and validating bespoke analytical methods tailored to specific products, packaging systems, and client requirements.
Further Reading
Read the article published on the Pharmaceutical Technology website written by Frank Judge, Consultant Chemist, titled: Thoughts on Amendments to ISO10993-7 Medical Device Ethylene Oxide Sterilization Residues
