image: This is Kevin Edgar. view more
Credit: Virginia Tech
Two recent grants awarded by the National Science Foundation will help scientists in the College of Natural Resources and Environment create new ways to use renewably sourced plant and wood polymers -- chemical compounds in which molecules are bonded together in repeating chains -- to tackle long-standing challenges in medical drug solubility and lignin utilization.
Kevin Edgar, professor in the Department of Sustainable Biomaterials and associate dean of Virginia Tech's Graduate School, has been conducting research on the design of biodegradable, sustainably based polymers that can help enhance the abilities of orally administered drugs to reach the bloodstream.
Edgar's research, in a joint project with Lynne Taylor, professor of industrial and physical pharmacy at Purdue University, focuses on using polymers designed from cellulose, the structural component of plants. The polymers work to prevent the crystallization of a drug's molecules when it is in pill form and during transport through the gastrointestinal (GI) tract so that medication can effectively reach the bloodstream.
"The method that we use requires a specific mix of polymer and drug that ensures that the drug is so perfectly dispersed in the polymer that no two molecules of drug are next to each other," said Edgar, who is also affiliated with Virginia Tech's Macromolecules Innovation Institute. "Then the polymer has to be designed to release the drug within the GI tract, which is mostly water."
The applications of Edgar's research are wide-reaching. Many current medications have solubility issues; to ensure that enough medication reaches the bloodstream, patients are prescribed higher doses. The excess drugs that are not absorbed from a patient's GI tract have the potential to cause toxic side effects and carry the risk of negatively impacting water treatment systems when they pass through the body. Drugs currently in development that may cause toxicity due to these solubility issues could be used successfully with assistance from natural polymers, bringing powerful new drugs to patients.
The development of a new polymer that can increase bioavailability for a range of drugs has the potential to improve current medication regimens, minimize patient side effects, and reduce drug costs.
Edgar and Taylor have already made strides in the field of polymer research to prevent drug crystallization, with 35 joint publications credited to their research groups. The current NSF grant is for $750,000 over three years.
Li Shuai, assistant professor in the Department of Sustainable Biomaterials, has been working to develop a new chemical process to replace current petroleum-reliant resins with a renewable material made from lignin, an organic polymer found in trees. Lignin is a waste product of the paper pulping process and is typically burned as a low-value fuel.
"Cellulose is the fiber that maintains the cell wall," Shuai said. "If you just have cellulose fiber, a plant cannot stand very well. It's like steel-reinforced concrete: you need both concrete and steel to maintain structure. Lignin polymer is a kind of natural glue or adhesive that holds the cellulose fibers together."
Shuai notes that the challenge of how to utilize lignin has existed since the pulping industry came into existence hundreds of years ago. He estimates that only 5 percent of lignin is currently developed into products, a number that he would like to see increase.
His research proposes a new catalytic process that will enhance the reactivity of lignin products, making them a useful alternative for a variety of industrial products, from kitchen countertops to adhesives.
"The structure of lignin is very complicated; it's very hard to utilize," Shuai noted. "I'm trying to break down the polymer into monomers, into single, small molecules, so that we can use them to make new polymers that will maintain their adhesive properties."
Lignin research holds the promise of replacing phenol formaldehyde resins, petroleum-based products that are widely used in manufacturing commercial products. Shuai hopes that finding a renewable alternative for this crucial resin will have additional positive effects on the environment by reducing the amount of lignin that reaches waste streams.
The NSF grant for Shuai's research is $300,000 over three years.
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