biocompatibility

September 5, 2017

Capacity of a material to fulfil its function with an appropriate response for a specific application from the receiving host.

Quality of being accepted in a specific living environment without adverse or unwanted side effects.

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Biomaterials are non-living natural or synthetic materials that are used in contact with the living body and must therefore be biocompatible as a primary requirement. Since there are different fields of application and exposure times for biomaterials in medical technology, biocompatibility is a context-related property and does not have an absolute definition. Over time, the existing definitions have been adapted and extended to new findings .

An important classification, especially for medical plastics, is the USP Class VI classification, which is described in the United States Pharmacopeia (USP), an annually updated manual for medicinal products (see Article 88). The biomaterials are subjected to in vivo tests in the following three areas: acute systemic toxicity, intradermal reactivity and a short-term implantation test.

Stricter requirements for approval are set out in DIN ISO 10993. In ISO-10993-1 the required tests are listed, while they are explained in the other ISO 10993 standards.

A USP Class VI classification is more time and cost effective than a test for ISO 10993 conformity and still provides an initial, good decision-making aid for manufacturers of medical devices as to which plastics are suitable. It depends strongly on the respective application which biocompatibility test is required.

Depending on the country, a conformity assessment procedure may also be required for the approval of medical devices, in the course of which a clinical trial may aditionally be conducted (partially by Reichelt Chemietechnik).

Wikipedia names 5 definitions for biocompatibility

  1. “The quality of not having toxic or injurious effects on biological systems”.
  2. “The ability of a material to perform with an appropriate host response in a specific application”, Williams’ definition.
  3. “Comparison of the tissue response produced through the close association of the implanted candidate material to its implant site within the host animal to that tissue response recognised and established as suitable with control materials” – ASTM
  4. “Refers to the ability of a biomaterial to perform its desired function with respect to a medical therapy, without eliciting any undesirable local or systemic effects in the recipient or beneficiary of that therapy, but generating the most appropriate beneficial cellular or tissue response in that specific situation, and optimising the clinically relevant performance of that therapy”.
  5. “Biocompatibility is the capability of a prosthesis implanted in the body to exist in harmony with tissue without causing deleterious changes”.