The growth of plastics in medical devices is growing exponentially around the world. Plastics are regulated like any other materials that may come in contact with human tissue or fluids and that usually falls under testing procedures issued under USP or ISO10993.
There are three time scales for biocompatible devices:
Limited - Less than 24 hour exposure
Prolonged - 24 hours to 30 day exposure
Permanent - 30 days and longer.
When determining biocompatibility, devices are categorized as follows:
Surface Devices - Items such as electrodes for monitoring, contact lenses, catheters, endotracheal tubes, sigmoidoscopes and similar devices.
Externally Communicating Devices - such as laprascopes, blood administration devices, pacemakers, oxygenators and the like.
Implant Devices - such as orthopedic pins or plates, heart valves, grafts, stents and similar devices.
Testing of these devices includes mechanical, thermal, chemical tests as well as systemic injection, intracutaneous and implantation. All of these must be done before a plastic component can be approved.
Typical materials for biocompatible applications include medical grades of PVC and Polyethylene, PEEK, Polycarbonate, Ultem PEI, Polysulfone, Polypropylene and Polyurethane.