ABSTRACT
Polyanhydrides are a class of bioerodible polymers that have shown excellent characteristics as drug delivery carriers. The properties of these biomaterials can be tailored to obtain desirable controlled release characteristics. Extensive research in this promising area of biomaterials is the focus of this chapter. In the Šrst part of the chapter, the chemical structures and synthesis methods of various polyanhydrides are discussed. This is followed
CONTENTS
Introduction ................................................................................................................................... 47 Background ....................................................................................................................................48 ClassiŠcation .................................................................................................................................. 49
Aliphatic Polyanhydrides ....................................................................................................... 49 Unsaturated Polyanhydrides.................................................................................................. 49 Aromatic Polyanhydrides ....................................................................................................... 49 Other Polyanhydride Chemistries .........................................................................................50
Synthesis ......................................................................................................................................... 51 Melt Polycondensation ............................................................................................................ 51 Schotten-Bauman Condensation ........................................................................................... 52 Dehydrative Coupling ............................................................................................................. 52 Ring Opening Polymerization ................................................................................................53
Characterization ............................................................................................................................53 Chemical Structure and Composition ...................................................................................53 Molecular Weight .....................................................................................................................54 Thermal Properties ...................................................................................................................54 Phase Behavior..........................................................................................................................55 Stability ......................................................................................................................................55 Degradation and Erosion ........................................................................................................56
Polyanhydride-Based Drug Delivery Systems .........................................................................56 Biocompatibility .......................................................................................................................56 Drug/Polymer Interactions .................................................................................................... 57 Device Fabrication .................................................................................................................... 57 In Vitro Release .........................................................................................................................58 In Vivo Delivery ....................................................................................................................... 59
Conclusions .................................................................................................................................... 59 References .......................................................................................................................................60
by a discussion of the physical, chemical, and thermal properties of polyanhydrides and their effect on the degradation mechanism of these materials. Finally, a description of drug release applications from polyanhydride systems is presented, highlighting their potential in biomedical applications.
