Compounds derived from blue agave may be more effective way to deliver drugs to the colon

Compounds derived from the blue agave, a fruit used to make tequila, shows promise in early laboratory studies as a natural, more effective way to deliver drugs to the colon than conventional drug-carriers, according to chemists at the University of Guadalajara in Mexico.

The development could lead to improved treatments for ulcerative colitis, irritable bowel syndrome, cancer, Crohn's disease and other colon diseases, they say.

Drug delivery to the colon is an ongoing challenge to physicians. Many drugs are destroyed by stomach acids before they've had a chance to reach the intestine, where they usually are absorbed. Researchers have tried to circumvent this problem by inserting the drugs into carrier molecules that resist breakdown in the stomach but have had difficulty finding a suitable carrier compound.

The tequila compounds, a class of polysaccharides known as fructans, were developed by the scientists in Mexico into tiny microspheres that are capable of carrying existing drugs that are used to treat colon diseases. Because the compounds resist destruction in the stomach, they could allow more of the drugs to reach the colon intact and improve their effectiveness, the researchers say. Their study was presented today at the 233rd national meeting of the American Chemical Society.

"This study shows that the agave fruit is good for more than just tequila. It also has medicinal value," says study leader Guillermo Toriz, Ph.D., an assistant professor at the university. "Agave fructan is the ideal natural carrier of drugs for the colon."

Researchers have known for some time that fructans, which are polymers of fructose, are resistant to acid degradation and theorized that they might be a useful drug delivery vehicle. But only a few plant sources, such as agave, contain fructans in large amounts. The agave fruit is 80 percent fructans by weight when ripe, the researchers say.

Toriz and his associates extracted fructans from the blue agave, the base ingredient of tequila. They chemically modified the fructan compound to allow drugs to be encapsulated, making the drugs resistant to degradation in the digestive system.

The researchers then prepared microspheres of the compounds and filled them with ibuprofen as a model of drug delivery to the colon. In laboratory tests, the ibuprofen-filled microspheres were exposed to hydrochloric acid for an hour and appeared physically intact upon subsequent microscopic examination, the scientists say.

Topiz and his research group currently are working on improving the durability of the fructans and plan animal studies in the future. If further studies show promise, human studies of the agave microspheres are anticipated. Funding for the study was provided by the Mexican National Science and Technology Council.

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