Medical Plastic Data Service Magazine



Our 30th Year of Publication
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Importance Of Biocompatibility For Medical Polymers

And Regulatory Requirements



K. R. Navaneethakrishnan, MSc, ERT
Assistant Director,
GLR Laboratories Private Limited, Chennai

Medical polymers are a blessing in disguise. Polymers have played a big part in the creation of medical devices in recent years due to their low density, which means they are light in weight, which is another advantage for patients if they are implanted. Injection moulding on a big scale allows for the creation of complicated shapes at a lower cost, as well as the ability to develop a material to match a specific application.

In the case of medical devices, the commonly used polymer groups are:: non-degradable synthetic polymers (e.g. polyethylene, polymethylmethacrylate, silicone); naturally occurring polymers (e.g. cellulose, alginate, gelatin, collagen); and biodegradable polymers (e.g. poly (L-lactic acid) (PLLA), polyglycolic acid). Examples of devices made of polymers are listed below:

Polypropylene or PP disposable syringes, membranes for membrane oxygenators, connectors
Polyvinylchloride or PVC - intravenous (IV) tubing, blood bags
Polyethersulfone or PES anesthesia masks, single and multi-lumen tubing
Polytetrafluoroethylene or PTFE surgical sutures, catheters
Polyurethane or PU catheters, medical gloves, and wound dressings
Polyetherimide, PEI surgical skin staplers
Polycarbonate or PC artery cannulas, stopcocks, luers, blood filter housings, dialyzer housings, insulin pens, surgical device
Polysulfone or PS Membranes and fluid handling applications
Polyetheretherketone or PEEK dentistry products, rigid tubing, catheters, disposable surgical instrument
Polypropylene or PP syringes, and closures, sutures, drapes, and gowns, medical trays
Polyethylene (PE-UHMW or PE-LD & HD) orthopedic sutures, tubing, packaging films, pouches, knee arthroplasty and total joint replacement.

Because most naturally produced polymers are found in the structural tissues of living animals, they have various advantages over synthetic polymers, including biocompatibility, biodegradability, and biological activity. Synthetic polymers can be customised to fulfil a certain absorption time requirement, thus improving repeatability and scale-up while avoiding the risk of disease transmission that naturally occurring polymers often provide.

Polymers have found their way as a convincing solution for many medical conditions in the form of various innovative medical devices. Nevertheless, it cannot be taken for granted that the use of medical polymers is risk-free. The impact of the quality of the raw material used, the manufacturing process, process additives, packaging materials used and the sterilization method used, each one of these parameters can contribute to the risk. In order to explore and fully utilize the tremendous benefits that medical polymers can offer, we need to study their biocompatibility.

Lack of biocompatibility of a device can result in a variety of biological and non-biological problems. When these dangers come into contact with the human body, they have the potential to cause injury. Chemicals present in the medical device that can enter the human body, implants that might trigger an immune response, deformed or damaged materials or portions of a medical device, and so on are some examples of potential causal risk agents. Polymeric materials often contain a small amount of Low Molecular Weight Chemicals (LMWC) such as additives, catalyst, processing aids, and radiation products. These LMWC may be potentially genotoxic.

Biocompatibility can be defined as the relationship between a material and the organism so that neither produces undesirable effects. Biological evaluation of medical devices is a mandatory regulatory documentation for medical device registrations. This documentation comprises of the biological evaluation plan (BEP) and the biological evaluation report (BER), as part of a risk management process in accordance with ISO 14971:2019 (Medical devices Application of risk management to medical devices), Annex I. This risk management process involves identification of biological hazards, estimation of the associated biological risks, and determination of their acceptability. According to ISO 10993- 1:2018 (Biological evaluation of medical devices Part 1: Evaluation and testing within a risk management process), the biological evaluation shall be planned, carried out, and documented by knowledgeable and experienced professionals.

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