Drugs Made From Polymers, The Stuff Of Plastics

Washington, Aug. 22 - A potentially safer, more potent form of aspirin - made from the same polymers that are the stuff of plastics - was described here today at the 220th national meeting of the American Chemical Society, the world's largest scientific society.

Others have used polymers as carrier molecules to deliver drugs and housed drugs within polymer capsules. But this is believed to be the first time that a polymer has been used as a drug itself, says Kathryn Uhrich, Ph.D., the principal investigator of the study and a professor of chemistry at Rutgers University in Piscataway, N.J.

"It sounds so simple, but nobody's ever done this before," says Uhrich, who foresees making other beneficial drugs into polymers. "We think there is great potential for these polymers."

Called PolyAspirin™, the drug consists of about 100 individual molecules of aspirin strung together in a chain to form an elastic compound, or polymer. A promising treatment for diseases ranging from inflammatory bowel disease to tuberculosis, it could eliminate stomach irritation and other side effects of using aspirin, reports the researcher. She expects human clinical trials to begin within two years.

New uses for aspirin, or acetylsalicylic acid, continue to be discovered. Once taken mainly to manage pain caused by headaches and arthritis, the versatile drug now helps prevent heart attacks and strokes. Some researchers believe it might be able to help prevent cancer and Alzheimer's disease as well.

But aspirin has a downside. In the stomach, it breaks down into its active ingredient, salicylic acid. As the stomach lining is sensitive to this acid, prolonged use of the drug can result in bleeding and stomach ulcers.

The structure of PolyAspirin™ allows it to dodge the stomach's acidic environment and break down into salicylic acid later - primarily when it hits the intestine's alkaline environment, where it is absorbed. As a result, the medication is delivered more efficiently and sticks to its target better, Uhrich says. This could mean taking smaller pills and using them less frequently, she notes.

PolyAspirin™ recently exhibited another, unexpected benefit: Mice given the drug grew 37 percent more new bone than a control group. This suggests additional potential uses: treating gum disease, coating orthopedic pins, and helping people heal after hip-replacement surgery, the researcher says.

Uhrich and her associates are also making a polymer version of para-aminosalicylic acid, a drug used to treat tuberculosis that can irritate the stomach - a side effect they hope to avoid.

Other possibilities include polymer versions of antibiotics that release medication slowly over time and surgical sutures that deliver anti-inflammatory drugs even as they dissolve.

Funding for this research was provided by the National Institutes of Health, DuPont and Johnson & Johnson.

The paper on this research, POLY 253, will be presented at 9:50 a.m., Tuesday, Aug. 22, in the J.W. Marriott Hotel, Capitol Salon E. See page 129 in the final program.

Kathryn Uhrich, Ph.D., is an associate professor of chemistry at Rutgers University in Piscataway, N.J.

A nonprofit organization with a membership of 161,000 chemists and chemical engineers, the American Chemical Society publishes scientific journals and databases, convenes major research conferences, and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.