Polyketal microparticles show promise as drug delivery vehicle

A family of biodegradable polymers called polyketals and their derivatives could improve treatment for such inflammatory illnesses as acute lung injury, acute liver failure and inflammatory bowel disease, say researchers at the Georgia Institute of Technology.

Niren Murthy, an assistant professor in Georgia Tech's Department of Biomedical Engineering, has developed biodegradable polymers that may improve the treatment of acute inflammatory illnesses by delivering drugs, proteins and snips of ribonucleic acid to disease locations in the body.

"The polyketal microparticles we developed are simply a vehicle to get the drugs inside the body to the diseased area as quickly as possible," said Murthy.

The major advantage to using these polyketals to deliver drugs is that they degrade into biocompatible compounds that don't accumulate in a patient's tissue or cause additional inflammation. Researchers at the institute have already produced a new polyketal derivative aimed at enhancing the treatment of inflammatory bowel disease.

The new polymer has the advantage of stability in both acids and bases. It degrades only in the presence of reactive oxygen species, which are present in and around inflamed tissue. Cell culture experiments have demonstrated that the microparticles degraded more rapidly in cells that overproduced superoxide, a reactive oxygen species.

The researchers are currently collaborating with Didier Merlin, a professor in the Division of Digestive Diseases at Emory University, to investigate loading these polyketals with therapeutics to treat inflammatory bowel disease.

"We think these microparticles are going to be fantastic for oral drug delivery because they can survive the stomach conditions before they release their contents in the intestines," said Murthy. Murthy's group is also examining the use of polyketals to treat acute liver failure - a condition in which the liver stops functioning because macrophages in the liver create reactive oxygen species.

Nick Crisp, professor of microbiology and immunology at the University of Rochester Medical Center, and Robert Pierce, currently head of anatomic pathology at Schering-Plough Biopharma and formerly of the University of Rochester Medical Center, are collaborating on this project.

Georgia Tech, Emory and the University of Rochester have filed three patent applications on the polyketal drug delivery system.