Polyhydroxyalkanoate compositions having controlled degradation rates

The present application provides a biocompatible medical implant comprising poly(4-hydroxybutyrate) homopolymer. Optionally, the implant is sterile. The implant may, for example, be selected from guided tissue regeneration devices, tissue engineering devices, tissue engineering scaffolds, foams, coatings, meshes, microparticles, resorbable wound closure materials such as suturing and stapling materials, controlled release devices, drug delivery devices, cell encapsulation devices, targeted delivery devices, devices with biocompatible coatings, orthopedic devices, prosthetics, bone cements (including adhesives and/or structural fillers), diagnostic devices, rods, bone screws, pins, surgical sutures, stents, patches (such as hernial patches and pericardial patches), devices with vascular applications, and tubes suitable for the passage of bodily fluids. The invention also provides a method for preparing a biocompatible polyhydroxyalkanoate that has a controlled degradation rate of less than one year under physiological conditions, and optionally processing thus prepared polyhydroxyalkanoate into a medical device. The biocompatible polyhydroxyalkanoate used in the method may, for example, be produced by a process selected from the group consisting of fermentation, enzymatic synthesis, chemical synthesis, melt processing, reactive blending, and recombinant techniques. The biocompatible polyhydroxyalkanoate used in the method may, for example, be derived by fermentation (a) using a co-feed, and/or (b) by a fermentation process that uses transgenic bacteria.