Biocompatibility: why it’s important for medical manufacturers and what you need to know.
Plastic has revolutionised the medical industry since its invention. It has enabled the delivery of life-saving diagnosis and treatment equipment to masses of patients worldwide. Plastic’s unique combination of properties combined with ease of use and relative low cost make it the perfect medical material.
Some examples of polymers in medical components are:
Polyvinylchloride / PVC — Blood tubing, blood bags
Polyethersulfone / PES — Single and multi-lumen tubing, catheters
Polytetrafluoroethylene / PTFE — Catheter linings, single and multi-lumen tubing, synthetic blood vessels, endoscopes, surgical sutures, reconstructive surgery, soft tissue regeneration patches
Polyethylene / PE-UHMW or PE-LD & HD — Surgical cables, artificial tendons and orthopaedic sutures, tubing
Polyurethane / PU — Breathable wound dressings
Polyetherimide / PEI — Reusable and sterilizable applications, surgical skin staplers
Polycarbonate / PC — Medical instruments and containers with glasslike transparency, check valves and tubing connectors
Polysulfone / PS — Surgical and medical devices, clamps, artificial heart components, heart valves
Polyetheretherketone / PEEK — Dentistry products, rigid tubing
Polypropylene / PP — Heart valve structures
However, with great power comes great responsibility, and that responsibility is safety.
Plastic is synthetic. It's not something that the human body is naturally designed to interact with, and so it is inherently important that any plastic that comes into contact with human body tissue is tested and certified as safe to do so.
Pure plastics have relatively low toxicity due to the chemical inertness and insolubility in water. But when combined with additives (as occurs during plastic production), their toxicity increases. Therefore, there are very stringent standards for the plastic industry, especially those meant for the medical devices.
The bottom line is this: polymers used in medical equipment that diagnoses or treats patients must be biocompatible.
Being ‘biocompatible’ means that a biomaterial (a biological or synthetic substance which can be introduced into body tissue) behaves and performs appropriately in a specific situation i.e. it is not toxic, reactive or injurious. All materials used in medical devices must be screened for biocompatibility so that they do not cause adverse local or systemic effects in people.
Biocompatibility depends on a plastic's chemical characteristics and how a device will be used, which determines the nature, frequency, and duration of patients' exposure to a polymer.
No single test may be sufficient to define biocompatibility, however the vast array of testing available includes those for acute, subchronic, and chronic toxicity; irritation to skin, eyes, and mucosal surfaces; sensitisation; hemocompatibility; genotoxicity; carcinogenicity; and reproductive effects. Tests that address specific organs or the immune or reproductive systems may also be needed.
Two common test regimens are used to measure biocompatibility: United States Pharmacopeia (USP) and International Organisation for Standardisation (ISO) 10993-1:2018 Biological evaluation of medical devices.
As a fully compliant facility, Matrix Medical Plastics prioritises quality and process control in every area of our service offering. As the UK’s first cleanroom extrusion facility, all medical products are processed and tested according to ISO Class 9 cleanroom regulations and under ISO 13485 quality management systems for medical devices. All ingredients used on site in the production of medical products meet the requirements of ISO 10993-1:2018 and USP Class VI. To find out more about our medical compounding capabilities, please get in touch with us here.