Sterilisation validation for medical devices – what manufacturers need to know and implement correctly!

The requirements for manufacturers of medical devices are constantly present in the regulatory world. Whether due to stricter regulations, more complex materials or international markets, knowledge of the targeted implementation of requirements is the decisive competitive factor. A special topic in healthcare is sterilisation validation, a central aspect of product and patient safety. This topic is given special attention with the involvement of experts, and not only during the certification process. Sterility is also a factor in building trust and long-term success in the market among users and patients. In this article, you will learn about the current regulatory requirements for sterilisation validation, how to select the optimal sterilisation method for your product, and which typical mistakes must be avoided at all costs. Using concrete practical examples, we show how validation can be carried out and documented safely, efficiently and in accordance with standards.

Just a few years ago, many manufacturers viewed the validation of sterilisation processes as a necessary documentation task, often only performed as the final step before market launch. However, with the entry into force of Regulation (EU) 2017/745, the continuous development of technical standards and the advance of new materials, the task profile has changed. Today, validation is an integral part of every development project and the continuous maintenance of product safety (re-validation).

Manufacturers who approach validation too late or incompletely face significant delays, increased audit costs, possible non-compliance and, in the worst case, product recalls. In order to minimise such risks from the outset, it is advisable to address all relevant requirements at an early stage and in a comprehensive manner and to implement a structured, multidisciplinary validation process.

At the start of a development project, companies should carry out a risk analysis in accordance with EN ISO 14971, in which the requirements for sterilisation, reprocessing and packaging are tailored to the specific product and material properties. This approach makes it possible to design the validation required at a later stage as continuous, verifiable evidence rather than treating it as an isolated mandatory task.

From ISO 11135 to ISO 17665: your guidelines for validation!

The regulatory framework for sterilisation validation at European level is primarily determined by Regulation (EU) 2017/745 (MDR). Essential requirements can be found in particular in Annex I, Chapter II, Number 11. This states that manufacturers of sterile medical devices must use procedures that are validated, monitored and documented in accordance with the state of the art in order to ensure sterility.

The following technical standards, among others, form the benchmark for the practical implementation of validation activities:

• EN ISO 11135: Reprocessing of medical devices using ethylene oxide.
• EN ISO 11137: Sterilisation of medical devices using ionising radiation, such as gamma or electron beams.
• EN ISO 17665: Sterilisation of medical devices using moist heat (steam).
• EN ISO 11737-1 and EN ISO 11737-2: Determination of the population of viable microorganisms (bioburden) and testing for sterility.
• EN ISO 11737-3: Testing for bacterial endotoxins
• EN ISO 17664: Information for the reprocessing of reusable medical devices.
• EN ISO 14937: General requirements for the characterisation of a sterilising agent and for the development, validation and control of the application of a sterilisation process for medical devices.
• EN ISO 13485: Quality management systems for medical device manufacturers, including the requirement for complete documentation and monitoring of all sterilisation processes.

These standards specify not only the methodology, but also the verification requirements and limit values, for example for the sterility assurance level (SAL), residues or the integrity of packaging after sterilisation.

In practice, this means that every single process step – from the selection of the procedure to the final product release – must be clearly defined, reproducible and comprehensively documented. Proper validation consists of installation qualification (IQ), operational qualification (OQ) and performance qualification (PQ), whereby PQ in particular must be checked regularly and revalidated in the event of product, process or packaging changes.

Method selection in sterilisation validation: requirements, standards and practice!

The selection of the appropriate sterilisation method is always the result of careful consideration of material compatibility, design requirements, product application and regulatory requirements. Steam sterilisation in accordance with EN ISO 17665 is considered the standard method for robust, temperature-resistant products such as surgical instruments or textile medical devices. For temperature-sensitive materials, complex cavities or electronic components, ethylene oxide in accordance with EN ISO 11135 is often recommended, as this method can reliably reach even hard-to-access areas.

Radiation sterilisation in accordance with EN ISO 11137, for example using gamma or X-rays, offers advantages for large quantities of disposable items such as syringes or cannulas. However, potential material changes, such as changes in physical properties or colour, must be assessed in advance as part of material testing. E-beam sterilisation is particularly suitable for delicate materials. However, restrictions on material density must be taken into account here, as E-beam cannot penetrate high-density materials.

It is crucial that all selected methods are validated in accordance with scientific principles in the respective context. This includes worst-case scenarios, such as testing for gas penetration in EO sterilisation or radiation resistance in gamma processes, as well as the selection and proper placement of biological indicators. Every detail, from loading the sterilisation chamber to the final sealing of the packaging, must be included in the validation concept.

IQ, OQ, PQ and monitoring: the building blocks of reliable sterilisation validation!

As required by specific standards, the validation process is divided into the phases of installation qualification (IQ), operational qualification (OQ) and performance qualification (PQ). While IQ focuses on the correct installation, calibration and documentation of all equipment, OQ serves to verify the process parameters and their stability in daily operation. Only in PQ is it then tested under practical conditions, such as maximum load, minimum process times or the most demanding packaging arrangements, whether the required sterility targets are actually achieved.

A key tool in everyday validation work are so-called bioindicators, as described, for example, in EN ISO 11138. These reliably indicate whether the selected process is microbiologically effective under real conditions. This is supplemented by chemical indicators, data loggers and the consistent documentation of all process and measurement data, such as temperature, pressure or humidity curves.

However, monitoring does not end with initial validation. Rather, MDR, EN ISO 13485 and also the specific standards require continuous monitoring and regular revalidation in the event of changes to the product, process or packaging. Manufacturers must be able to demonstrate at all times that all products supplied actually achieve and maintain the required degree of sterility. This is the only way to avoid market complaints, recalls and liability risks in the long term.

Typical pitfalls in sterilisation validation!

In practice, it has been shown time and again that companies integrate validation too late in the product development process. Those who only take the requirements of Regulation (EU) 2017/745 and the relevant EN ISO standards into account shortly before certification must expect costly re-planning, delays or even regulatory rejections.

Other typical errors include inadequate material testing, a lack of worst-case analyses, insufficient testing of packaging integrity and overly superficial documentation. Gaps in residue testing for ethylene oxide or insufficient validation in the selection and use of indicators are particularly critical. Such errors are quickly detected in audits and lead to rework, loss of time and increased costs.

Those who take a comprehensive, multidisciplinary approach can systematically minimise these risks. It is advisable to draw on the expertise of experienced regulatory affairs specialists, specialised laboratories and materials scientists at an early stage.

Best practices for successful sterilisation validation!

Successful manufacturers do not view sterilisation validation as a bureaucratic burden, but rather as a means of actively shaping product safety and, through risk-based and stringent planning, achieving certification more quickly than their competitors. They involve all relevant departments from the outset, define clear responsibilities and rely on comprehensive, complete documentation. Close cooperation with external testing laboratories, the use of modern monitoring technologies such as data loggers and consistent staff training are now standard features of professional validation management.

It is also important to continuously adapt the validation strategy to new regulatory requirements and technical innovations. The international harmonisation of standards, the increasing importance of sustainability aspects in the selection of sterilisation processes, and the digital transformation of process monitoring will become even more important in the future.

Strategically designing sterilisation validation – with the right expertise!

Sterilisation validation is now a key quality promise to customers and patients. It not only protects against regulatory risks, but also protects patients in particular. Manufacturers who implement the validation process holistically, carefully and in accordance with applicable laws and standards secure their access to the medical device market.

Now is the ideal time to critically examine existing validation processes, incorporate new regulatory developments and work with experienced partners to develop a future-proof validation strategy.

TentaConsult provides comprehensive support in selecting the optimal sterilisation methods, validating all processes in accordance with standards and aligning your quality management with the requirements of the coming years. Feel free to contact us for sound, practical advice. Sterility is not a formal criterion, but a value proposition and a responsibility towards people.