Device uses ultrasound to deliver drugs

Sound waves create tiny bubbles of fluid as a medication is being delivered rectally. Carl Schoellhammer and Giovanni Traverso

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A small ultrasound device can rapidly deliver high doses of medications directly to the gut — opening a path to potential new treatments for intestinal disorders such as irritable bowel syndrome, a Boston-based research team reported Wednesday in the journal Science Translational Medicine.

Medication for conditions such as IBS, Crohn’s disease, and ulcerative colitis are typically delivered through nightly rectal enemas. The new approach uses sound waves to create tiny bubbles of fluid as the medication is being delivered rectally. When the bubbles burst, they create microjets that push the drug directly into intestinal tissue.

The treatment can help push drugs such as mesalamine, which is often used to treat colitis, into diseased tissues in as little as one minute. The device was tested on rodents and pigs but has not yet been tested in humans.

Massachusetts Institute of Technology engineer Robert Langer, a veteran of drug and device development, helped guide the research with a team of other scientists from MIT and Massachusetts General Hospital. They found that using ultrasound enhanced absorption of the drugs they tested up to tenfold — a gain that might let patients use the enemas less often and hold them in place for shorter amounts of time.

“We can potentially decrease the amount of time medicine is in place and require more infrequent treatments,” said gastroenterologist Dr. Giovanni Traverso, who worked on the study.

“The utility of this would be for people with more mild or moderate forms of these diseases,” said Dr. Adam Cheifetz, director of the Center for Inflammatory Bowel Disease at Beth Israel Deaconess Medical Center. He was not involved in the study.

While the research focused on inflammatory diseases of the gastrointestinal tract, researchers said it could also be used to administer a wide range of drugs, including vaccines, antibodies, and chemotherapy. They’re working on a miniaturized version of the ultrasound probe. They’re also exploring the potential for ingestible capsules that would emit sound waves as they traveled through the gut.

Some patient advocates said they worried that the treatment might damage tissues, especially since people with inflammatory gastrointestinal diseases often already have very sensitive intestinal tracts.

Patients with ulcerative colitis, for instance, can have “fissures, or fistulas or inflammation,” said Kim Snapper, executive director of the New England chapter of the Crohn’s and Colitis Foundation of America.

Cheifetz suggested that the possibility of damage is unlikely in patients with the mildest forms of these diseases. “But you would have to know how strong the sound waves are,” he added.

The research team examined this issue by doing biopsies of mice with colitis after they were treated with the ultrasound device. (The pigs in the study did not have intestinal diseases.) “We looked at the tissue right after the treatment, and we did not see a lot of damage in the rodents suffering from colitis,” Traverso said.

Langer has been studying the use of ultrasound for drug delivery for three decades. Back in 1985, he co-wrote a study showing that sound waves could help drugs penetrate the skin. But he had not explored the technique in the intestinal tract until now.