ABSTRACT
Polyhydroxyalkanoate (PHA), a naturally occurring microbial biopolymer had been studied in detail in terms of its production, properties and applications. This biopolymer is completely biodegradable and some PHA is known for its biocompatibility. PHA and some of its blends and composites have been tailored as suitable biomaterials and are extensively studied for various pharmaceutical and medical applications (Williams and Martin, 2002; Frier, 2006). These PHA polymers have been tested in tissue engineering applications as surgical sutures, bone plates, implants, gauzes, osteosynthetic materials and also as matrix material assisting slow release of drugs and hormones (Zinn et al., 2001; Williams and Martin, 2002; Sudesh, 2004). Most of the PHA-based biomaterials studied are constituents of this polymer containing 3-hydroxybutyrate (3HB) and/or 4-hydroxybutyrate (4HB) units. These monomers were identified as normal constituent of human blood (Wiggam et al., 1997). Fresh human blood has been found to contain 0.17-1.51 mg/L of 4-hydroxybutyric acid (Sudesh and Doi, 2000). Hence, much effort has been devoted to produce P(4HB) homopolymer and P(3HB-co-4HB) copolymers with improved biomaterial properties. TephaFLEX® is an example of the latest biomaterial derived using these polymers for the fabrication of medical devices by Tepha Inc. (Tepha Medical Devices). P(4HB) and P(3HB-co-4HB) copolymers have gained much interest for a wide range of medical and pharmaceutical applications (Chee et al., 2008; Yang et al., 2002). This chapter will discuss the P(3HB-co-4HB) copolymer as well as its blends and composites as a biocompatible material in the medical and pharmaceutical fields. The fabrication of P(3HB-co-4HB) copolymer and its blends or composites with varying monomer compositions and properties will be reviewed. The application of resulting biomaterials in the medical field will be summarized.
