Cleaning & Sterilization Procedure

Purity of Medical Devices – Cleaning and Sterilization Procedure

As a manufacturer of medical devices, you are required to ensure that all foreseeable risks are excluded or reduced as far as possible for each medical device in its intended use. These include, among other things, risks that remain after delivery due to a high degree of contamination on the product surface, e.g. due to production residues (Essential Safety and Performance Requirements of the MDR, Annex I).

In order to be able to market medical devices that are compliant and in an appropriate state of cleanliness, the manufacturer is required to make sure that all critical contamination can be reduced as much as possible and that all acceptance criteria are fulfilled. To provide this proof, a validation of the cleaning process must be carried out during production. In this process, the initial condition of the medical device before cleaning is first determined in various laboratory tests. These include, for example, tests for existing bioburden, particles, cytotoxicity or organic impurities. The results of the initial condition serve as a reference value for the subsequent laboratory tests on the medical devices after at least three independent cleaning batches. The performance of the cleaning and thus the cleanliness of the medical devices can be determined from this. The VDI standard 2083 Part 21 and, in addition, DIN/TS 5343 are to be considered as normative bases for this.

The testing strategy for determining cleanliness is developed individually depending on the defined acceptance criteria. Either a real or simulated product is to be used as a test specimen. This is to be selected or constructed on the basis of a worst-case assessment. The scope and frequency of testing is to be determined in accordance with a suitable sample calculation, considering the batch sizes and in consultation with the testing laboratory.

The performance of cleaning validation is not only due to medical necessities (exclusion of unwanted physiological reactions), but also to technical (e.g. impairment of the adhesion of coatings or subsequent processes due to chemical residues) or visual (e.g. cleaning streaks) necessities that influence the intended use of the medical device.

Periodic cleaning performance verifications, according to risk-based defined time intervals, must be carried out. These may be shortened if changes are made to the product design or manufacturing processes that could potentially affect cleanliness. The necessity and extent of revalidation must be justified on the basis of the results of the review and taking into account the reproducibility of the process, the risks associated with any contamination, and the frequency and scale of manufacture.

Many manufacturers are unsuccessful in their search for defined limit values for biological, chemical or particulate contamination. This is because, as a rule, no limit values have been defined! Due to the complexity of medical technology and the large number of medical devices, it has not yet been possible to define limit values by law or by standards. This means that each manufacturer has to determine their own limit values (acceptance criteria). This approach is called the “risk-based approach”.

We see ourselves as specialists in cleaning validation and the cleanliness of medical devices. In our own laboratory, we carry out tests for cleaning, reprocessing and permanent quality control. We are here to support you in this area in the context of certification of your medical devices.