New Technical Information Reports (TIRs) published recently by AAMI provide guidance for meeting the requirements of American and International Standards for industrial sterilization.

TIR 15, Ethylene oxide sterilization equipment, process considerations, and pertinent calculations, supplements the information contained in ANSI/AAMI/ISO 11135 (industrial EO sterilization). This TIR addresses equipment and engineering issues not covered in 11135 and provides guidance on determining minimum product temperature prior to preconditioning and on calculating relative humidity and EO concentration in the load or sterilization chamber.

TIR 19, Guidance for ANSI/AAMI/ISO 10993-7:1995, Biological evaluation of medical devices - Part 7: EO sterilization residuals, provides a roadmap for those using the 10993-7 standard to assess residues on EO-sterilized medical devices and determine whether the residue level is acceptable for the intended use of the device.  The report’s two-page flow chart outlines the steps required under 10993-7, shows the decision points in the standard, and provides guidance for choosing the appropriate action when alternatives are allowed.

TIR 22, Guidance for ANSI/AAMI/ISO 11607:1997, Packaging for terminally sterilized devices, fills gaps in that standard concerning packaging materials selection and suggests test methods that can be used to qualify package forming and sealing. In addition, a special annex on package validation is included.

TIR 17, Radiation sterilization-Material qualification, is a companion document to ANSI/AAMI/ISO 11137:1994 (radiation sterilization). While the need to consider possible effects of radiation sterilization on materials commonly used in medical devices or packaging is briefly reviewed in 11137, TIR 17 offers much more detail and guidance on the steps necessary to assess the compatibility of materials with this process. Extensive guidance on accelerated aging techniques is also provided.

Two new ISO standards for sterilization have recently been released. The new standards are:

ISO 11737-2, Sterilization of medical devices - Microbiological methods - Part 2: Tests of sterility performed in the validation of a sterilization process, that specifies the general criteria for tests of sterility on medical devices that have been exposed to a treatment with the sterilizing agent that is a fraction of the specified sterilization process, and

ISO 14160, Sterilization of single-use medical devices incorporating materials of animal origin - Validation and routine control of sterilization by liquid chemical sterilant. This provides criteria for the use of liquid sterilants applied to devices of animal origin.