Sterile Matters

16 September 2007 (Last Updated September 16th, 2007 18:30)

The growth of medical device markets has prompted further review of sterilisation standards. Johnson & Johnson's Eamonn Hoxey explains to Nic Paton how they have changed.

Sterile Matters

It is now more than a decade since the first European and international standards for sterilisation were published (1994 and 1995 respectively). As technology and medical devices continue to evolve and improve, the need to keep standards reviewed and updated, and for end users and manufacturers to keep firmly up to date, remains as imperative as ever.

Consolidation and mergers and acquisitions among multinational companies, the expansion of the EU and the desire of many countries to export either goods to the US or Europe have been key drivers of this process. The booming growth of Asian markets has also made developing standards a primary objective of many medical device companies. The accelerating development of medical-grade materials for construction and packaging films is another important factor.

NEW GUIDELINES

Previously, explains Eamonn Hoxey, executive director for Europe, the Middle East and Africa at Johnson & Johnson Quality & Compliance Worldwide, the standards were reviewed every five years. But in 2000 a more extensive revision process was initiated, led by the International Organization for Standardization.

‘Standards undergo a regular and systematic periodic review to ensure that they remain "fit for purpose" and continue to reflect the state of the art,’ he argues. ‘This is particularly important where standards have a regulatory application. In the case of sterilisation standards, the formal review process was initiated in 2000, five years after the initial publication.

"As part of this, the decision was made not only to update the standards in the light of technical developments, but also to undertake the revisions jointly between the international and European standards organisations," he adds.

In addition, the decision was made to use a common format and coordinate the activity, to ensure that the terminology and content was consistent across the processes. The advantage of this is twofold, argues Hoxey. First, for those who apply more than one method of sterilisation, there is now a more consistent basis from which to work. Second, it provides a measure to make sure that the requirements for the different processes are specified in the same level of detail.

REVISIONS OF STANDARDS

So what has changed? The standards are divided into three parts: requirements for development, validation and routine control of a sterilisation process for medical devices, establishing the sterilisation dose and guidance on dosimetric aspects. The revision process has been wide-ranging, covering a number of important areas. These include the need to assess the impact of the sterilisation process on the environment; and a requirement to define systems to ensure the microbiological quality and cleanliness of any products presented for sterilisation and to estimate bioburden at defined intervals.

There are changes in the regulation regarding the use of a research steriliser, changes around microbiological performance qualification, physical performance qualification and validation parametric release. There are revisions, too, around routine monitoring, product release, requalification and determining process lethality. Other important changes include those in sterilising agent characterisation, approaches to physical and biological monitoring, the use of product families, retained tests and the use of process challenge devices.

Hoxey cites getting consistency across the processes as a significant achievement but also focuses on a number of key changes: "In ISO 11137 for radiation sterilisation, the inclusion of ISO 11137-2 on establishing the sterilisation dose, with the addition of methods of dose substantiation; and in ISO 11135-1 for ethylene oxide, the acknowledgement of parametric release as a mainstream release approach, rather than an 'add on' as it was in the previous edition of the standard."

FUTURE EFFECTS

So what will be the main impact of these changes for manufacturers/end users? Hoxey stresses that the intention has not been to raise the regulatory bar during the revision process, but simply to recognise the advances in validation and routine control that have been made since 1994. Areas such as the increased recognition of parametric release in EtQ sterilisation and new and improved methods of establishing the sterilisation dose in radiation sterilisation have substantially improved on previous standards.

"The new standards are a sign that European and international cooperation in the development of standards has improved significantly."

"For manufacturers, the technical updating opens the doors to some improvements in developing and validating sterilisation processes," explains Hoxey. "The wide acceptance or parametric release for ethylene oxide and the inclusion of methods of dose substantiation at 25kGy and 15kGy for radiation sterilisation are, in my view, major examples."

For users of medical devices there is no change as the standards continue to reflect the state of the art in development, validation and routine control of sterilisation.

The new standards are also a sign that European and international cooperation in the development of standards has improved significantly. The result has been the creation of 'a substantial body of standards', the majority of which have now been adopted as both European and international standards.

There is also good news in that there is a three-year transition period before the previous versions of the standards become obsolete. Nevertheless, it is a good idea to start working now to ensure all processes are updated and revised in accordance with the new standards. Manufacturers of medical devices, particularly those whose products are supplied internationally, need to take dynamic action to ensure they are on track.

"Obtain copies of the new standards," he advises. "Make sure your staff in research and development, who are working on the development of devices requiring sterilisation, are aware of the new standards so that they are taken into account in the development process. Finally, review your processes and procedures against the new standards, undertake a gap analysis and have an action plan to comply."