Popping the poly pill

Plastic pills promise new treatments

A safer, more potent form of aspirin could soon be in your medicine cabinet.

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.

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.

"It sounds so simple, but nobody's ever done this before," said Professor Kathryn Uhrich of Rutgers University in Piscataway, New Jersey at a meeting of the American Chemical Society on Tuesday.

She expects human clinical trials to begin within two years.

Smaller doses

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 in the intestine, which is alkaline and therefore neutralises the acid.

As a result, the medication is delivered more efficiently, which in turn means smaller pills and taking them less often.

Professor Uhrich and her associates are also making a polymer version of para-aminosalicylic acid, a tuberculosis treatment that can irritate the stomach.

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