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Researchers Develop Long-term Drug-release Capsule

This star-shaped structure with six arms can be folded inward and encased in a smooth capsule, which can be swallowed. Once in the stomach, the capsule opens and medicine is released in measured doses. (Photo courtesy of Melanie Gonick/MIT)

U.S. researchers have developed the first long-lasting capsule that, when taken orally, slowly releases medication into the body. The drug-delivery system was developed for the treatment of malaria, though it could contain medications for a number of diseases.

Once inside the stomach, the plastic capsule springs open into a star-shaped form that contains the drug, which is released in measured doses. The polymer material is designed to initially resist the stomach's hostile acidic environment, although the device dissolves after two weeks and is expelled harmlessly through the digestive tract. At that point, a patient would swallow another drug-containing capsule.

A study describing the capsule and its development was published in the journal Science Translational Medicine.

Researchers see potential applications for the system in psychiatric medicine, diabetes care, and treatment for cardiovascular disease. Slow-release formulas of different pharmaceutical agents would have to be developed for use in the capsule.

Researchers have tested the capsule containing ivermectin, an agent that's used to treat parasites.

Scientists from Massachusetts Institute of Technology and Brigham and Women's Hospital in Massachusetts chose ivermectin in their experiments because of an observation made when the drug was used to treat river blindness in Africa, where malaria is endemic.

"What was observed was that malaria would transiently drop,” said Giovanni Traverso, a research associate at Brigham and Women's Hospital. “And so what we proposed was, ‘What if we could increase the period of time during which individuals could have ivermectin in their system, really to help suppress the mosquito population in those regions?’”

Ivermectin kills the mosquitoes that carry the malaria parasite. Ninety percent of malaria cases occur in sub-Saharan Africa.

In the case of malaria, one potential scenario is that the capsule be paired with another drug, such as artemisinin, to help drive down the number of malaria cases.

According to the World Health Organization, about 50 percent of people in the West and 30 percent of people in developing countries take their medicine every day, as prescribed. A computer model predicts that the capsule could improve adherence to at least 70 percent.

Many times people forget to take their daily medicine, their symptoms are mild, or they want to forget that they have a chronic disease, said Andrew Bellinger, one of the researchers at MIT.

"You can take advantage of the fact that patients don't have to be reminded every day that they need to take their medicine,” he said. “They can remember once a week to take their medicine, and then live normal lives the rest of the time."

Experiments have been successfully conducted in pigs and dogs. Researchers are in the process of designing a human clinical trial expected to begin next year.