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Glossary · ISO and IEC standards for MedTech and pharma

ISO 11135 and ISO 11137

Also known as: ISO 11135:2014, ISO 11137-1:2006, EN ISO 11135, EN ISO 11137-1, Ethylene oxide sterilization, Radiation sterilization

ISO 11135 and ISO 11137 are the international standards for the development, validation and routine control of sterilization processes for health care products: ISO 11135 for ethylene oxide, ISO 11137 for radiation such as gamma, electron beam and X-ray. They require the process to be validated because sterility can't be verified by testing the finished product.

  • Standards
  • MDR
  • Pharma

In one sentence

ISO 11135 (ethylene oxide) and ISO 11137 (radiation) set requirements for developing, validating and routinely controlling sterilization processes.

Example

A manufacturer of sterile surgical drapes has its gamma sterilization dose established to ISO 11137-2, dose-mapped at the contract sterilizer and verified with quarterly dose audits, while its catheters are sterilized with ethylene oxide under a process validated to ISO 11135.

How it applies

  • Special process: Sterility of a batch can't be shown by inspection or sterility testing alone, so the process is validated and then kept under routine control. This is a typical special process in an ISO 13485 QMS.
  • Ethylene oxide (ISO 11135): Validation includes installation, operational and performance qualification, with microbiological and physical performance qualification. Routine control covers the process parameters of each cycle; EO residuals on the device are evaluated under ISO 10993-7, part of the ISO 10993 series.
  • Radiation (ISO 11137): Part 1 sets the requirements, part 2 the methods for establishing the sterilization dose, part 3 the dosimetry. Dose mapping establishes the minimum and maximum doses in the product load; periodic dose audits confirm that the dose remains valid for the bioburden.
  • Sterility assurance: For devices labeled sterile in the EU, a sterility assurance level of 10⁻⁶ is the usual requirement for terminally sterilized devices (EN 556-1). Bioburden is determined under ISO 11737-1.
  • Amendments: ISO 11137-1:2006 has been amended; check the current consolidated version and the list of harmonized standards before citing it.
  • Technical documentation: Validation reports, requalification records, sterilizer or contract sterilizer agreements, batch release records and the sterile barrier system evidence belong in the technical documentation; the label carries the sterilization method using ISO 15223-1 symbols.

ISO 11135 vs. ISO 11137

Ethylene oxide penetrates packaging as a gas and suits heat- and radiation-sensitive materials, but it leaves residues that must be evaluated and needs aeration. Radiation acts through dose, is controlled mainly by dose and dosimetry, and releases products without aeration, but it can degrade some polymers. The choice affects material selection, packaging, biological evaluation and labeling, so it is made early in design.

By knowledge.aitechdoc.world · Published September 25, 2026 · Last reviewed

Source: ISO 11135:2014, Sterilization of health-care products — Ethylene oxide — Requirements for the development, validation and routine control of a sterilization process for medical devices; ISO 11137-1:2006, Sterilization of health care products — Radiation — Part 1: Requirements for development, validation and routine control of a sterilization process for medical devices

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Blog and are not part of any standard.

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