Biocompatibility defines the compatibility of a material with a living tissue. EU MDR requires evidences that all of the materials used in medical devices and coming in contact with the human beings are biocompatible. The manufacturers can opt for right strategies to make their devices compliant with the new regulations by checking that if they are at par with the ISO 10933.
Fundamentals of Biocompatiblity
Risks Arising Due to Lack of Biocompatibility
The medical device manufacturers should make their devices in a way that they are devoid of any potential risks. These risks include biological as well as non-biological risks. Examples of some of these risks are:
- Chemicals that can get inside the body from a medical device;
- Implants which can trigger an immune reaction inside the body;
- Materials of a medical device which can initiate an allergic reaction;
- Materials which change their form or get broken down in the patient’s body against the intentions of the manufacturers or
- Malfunctioning implants and materials.
Fundamental Terms and Definitions
There are some important terms defined by ISO 10933 in the context of biocompatibility. These definitions are biological risk, biological safety, biocompatibility, and host response.
- Biological Risk: ISO 10933 defines biological risk as
“Combination of the probability of harm to health occurring as a result of adverse reactions associated with medical devices or material interactions, and the severity of that harm.”
- Biological Safety: ISO 10933 defines biological safety as
“Attaining the freedom from unacceptable biological risks.”
- Biocompatibility: According to ISO 10933, he term biocompatibility can be defined as
“Ability of a medical device or material to perform with an appropriate host response in a specific application.”
- Host Response: The term host response in the upper definition means
“The potential undesirable actions which the host body can show against an implant or a medical device.”
Biocompatibility and Regulatory Requirements
The new Medical Device Regulations put a lot of emphasis on biocompatibility. This can be confirmed from the following sources:
- Annex I: General Safety and Performance Requirements:
The annex I corresponds to the general performance and safety requirements of the device by taking in account the intended purpose of the device, people involved in the transport of the device, storage, and use. The device shall be designed in such a way that risks posed by containments and residues of the medical devices, especially those coming in the direct contact with the live tissue should be minimized.
- Annex II: Technical Documentation:
Annex II requires the testing of all the medical devices. Test design, study protocols, data analysis methods along with test conclusions should be made available in the context of biocompatibility. Annex II requires the devices to be classified under their physical, chemical or microbiological role as well as on the basis of their contact with the patients, i.e. either direct or indirect.
The manufacturer shall submit a rationale documentation for the devices which have not underwent any testing.
- Annex VII: Requirements for Notified Bodies:
The staff of the notified bodies must be competent to understand the different aspects of biocompatibility. The Notified Bodies must also keep the manufacturers of medical devices in their sights to ensure that the manufacturers are using the latest scientific knowledge in terms of biocompatibility of materials.
Brief Guide On Standard Text
Most of the medical device manufacturers use ISO 10933-1 as their guiding tool, as it throws light on the evaluation of biological safety. This standard directs the manufacturers to make sure that their medical device ensure its biological safety throughout the lifecycle of a medical device.
ISO 10933-1; Clause – 4.7:
This part emphasizes acquiring freedom from unacceptable biological risks such as contaminants and residues, packaging materials, leachable substances and products that are the result of degradation.
Information Processing on Biocompatibility
Making the Use of Available Information
Manufacturers gather all of the available information in the form of material data sheets, certificates, market experiences and different researches.
Adding missing information
There are many factors that are often not mentioned yet they can alter the biocompatibility of a device. These factors can include cleaning of the device, interaction of different components of device with one another, material processing, changes that can occur in a device during its lifecycle etc.
Evaluating Existing Information
The manufacturers should critically evaluate the former information available on the medical devices and their components. Therefore, the manufacturers should be able to evaluate the existing information such as the test methods and parameters, raw materials used in the manufacturing of the product and the transferability of results. For the manufacturers who think that their products have been used on the market from many years and there is no need for them to evaluate their products, they should consider the production processes and tools used in the manufacturing of their products, all of the substances participating in the production process (colorings, additives etc.) and the final cleaning process.