Medical Device Link . Medical Applications of Polycarbonate

Polycarbonate fills an important niche as one of the most popular engineering resins in the medical device market. Bisphenol-A polycarbonate has been commercially available since the 1960s, and its use in medical devices dates from approximately that time. Possessing a broad range of physical properties that enable it to replace glass or metal in many products, polycarbonate offers an unusual combination of strength, rigidity, and toughness that helps prevent potentially life-threatening material failures. In addition, it provides glasslike clarity, a critical characteristic for clinical and diagnostic settings in which visibility of tissues, blood, and other fluids is required. Because biocompatibility is essential for any material used in direct or indirect contact with patients, polycarbonate grades are available that comply with biocompatibility testing standards such as ISO 10993-1 and USP Class VI. A recently developed lipid-resistant polycarbonate formulation (Makrolon DP1-1805, Bayer Corp., Pittsburgh, PA) was used to manufacture components of a needle-free IV system (Safsite, from B. Braun Medical, Inc., Bethlehem, PA). Polycarbonate can be processed with standard injection molding equipment. It can also be blow-molded into hollow containers or extruded into film, sheet, and thick- or thin-walled tubing. Polycarbonate sheet and film can be thermoformed into various complex shapes. For short-run devices or prototypes, polycarbonate rod and slabs can be cut, milled, and machined to the desired configuration. In the medical market, sterilization is a crucial factor in the development of devices that have direct contact with patients. A key attribute for polycarbonate is that it can be sterilized using all major methods: ethylene oxide (EtO), irradiation (both gamma and electron-beam), and steam autoclaving. Polycarbonate can also be disinfected with common clinical disinfectants, such as isopropyl alcohol. This range of techniques offers the device designer broad flexibility in determining the most cost-effective method for a particular product. Polycarbonate is not suitable