ABSTRACT
This chapter addresses the formulation issues with respect to microspheres and discusses the possibility of obtaining surface eroding microspheres with polyanhydrides. The various microencapsulation processes which were developed and employed were designed to address all the physical properties in such a way as to enable microspheres to be produced given nearly any polymer property and monomer composition. The microspheres are spherical in shape and contain some pores on the surface; a cross-sectional view of the microsphere reveals a very porous internal structure which is typical of this particular process. Differential scanning calorimetry and X-ray analysis of the polymers, dyes, and drug loaded microspheres were performed in order to characterize the physical state of the polymers and dyes after microencapsulation. The chapter shows that by appropriate choice of polymer backbone and microencapsulation techniques, delivery systems with desired characteristics can be achieved.
