Foster Corporation specializes in melt extrusion blending and forming of highly regulated materials, including long term implant polymers and bioresorbable polymers.
Implantable polymers are custom formulated in a dedicated, highly regulated environment using precision hot melt extrusion blending and forming technologies. Implant polymers are manufactured in a cGMP clean room production facility using twin screw extruders that incorporate cGMP design for medical applications. Twin screw extruders have several advantages such as easy material feeding, high kneading and dispersing capacities, and short transit time. Screw elements, screw rotation and screw speeds can be custom designed for the formulation being produced.
Implantable Polymer Types
Implantable polymers commonly used for implantable devices can be categorized based on anticipated duration of the polymer in the body ranging from permanent to bioresorbable implants.
Long-Term Implantable Polymers – these include biodurable (non-resorbable) polymers such as polyethylene for limited structural applications to polyketones (PEEK) for spinal applications or sutures with structural performance approximating bone.
Bioresorbable Polymers – these include polylactide (PLA), polyglycolide (PGA) and copolymers of PLA/PGA which can be tailored to meet mechanical performance and resorption rates required for applications ranging from non-structural drug delivery polymer applications to resorbable screws or anchors.
Implantable Polymer Additives
Implantable polymers can be enhanced to improve application performance with biomedical additives to provide visibility on x-ray or stimulate bone growth.
Bone Mineral – Phase pure β TCP (tricalcium phosphate) is an osteoconductive and biocompatible additive melt blended with bioresorbable polymers such as PLA for stimulation of bone growth in applications such as ACL screws. Alternatively, hydroxyapatite (HA) may be melt blended with bioresorbables polymers such as PLLA for interference screw for anterior cruciate ligament (ACL) reconstruction.
Radiopaque Fillers - Polymers are inherently transparent to x-ray imaging and require specific additives to achieve x-ray visibility. Radiopaque fillers commonly blended with biomedical polymers for radiopacity include barium sulfate, bismuth subcarbonate, bismuth trioxide, bismuth oxychloride, and tungsten.