An Overview: Use of Polymer Microspheres in Controlled Drug Delivery

Polymer microspheres can be employed to deliver medication in a rate -controlled and sometimes targeted manner. Microspheres from which therapeutic agents may be released at controlled rates for long periods of time, ranging from days to months. Such systems offer numerous advantages over traditional methods of drug delivery, including tailoring of drug release rates, protection of fragile drugs and increased patient comfort and compliance. Polymeric microspheres are ideal vehicles for many controlled delivery applications due to their ability to encapsulate a variety of drugs, biocompatibility, high bioavailability and sustained drug release characteristics. This review describes methods of microsphere preparation and the major factors controlling the release rates of encapsulated drugs. Furthermore, pharmaceutical applications and recent advances in the use of polymer microsphere based systems for delivery of single shot vaccines, plasmid DNA and therapeutic proteins are discussed, as well as some future directions of microsphere research.