The ultrasound creates tiny bubbles that implode, forming microjets that push the drug into the tissue.
Image credit: MIT
Now, new research from the Massachusetts Institute of Technology (MIT) and Massachusetts General Hospital (MGH) reported in Science Translational Medicine shows that ultrasound could be a way to hasten drug absorption in the gastrointestinal (GI) tract.
One of the senior authors, Dr. Giovanni Traverso, a gastroenterologist and researcher who works at both institutions, says:
"We're not changing how you administer the drug. What we are changing is the amount of time that the formulation needs to be there, because we're accelerating how the drug enters the tissue."
It appears that ultrasound disrupts the tissue barriers that normally limit the throughput of drugs passing through the GI tract into the bloodstream.
The researchers demonstrated this effect on pigs, where they found ultrasound drove both insulin, a large protein, and mesalamine, a smaller molecule often used to treat colitis, into the animals' colonic tissue faster than natural absorption.
Microjets push the drug through GI tissue
The researchers also found that ultrasound could resolve colitis symptoms in mice by speeding up the colonic absorption of mesalamine.
They followed the delivery of the drug with 1 second of ultrasound every day for 2 weeks. Giving the treatment every other day also helped, but delivering the drug without ultrasound had no effect, the authors note.
The technique works through "transient cavitation," a condition that arises when you expose a fluid to sound waves. It creates tiny bubbles that implode, forming microjects that push the drug into the tissue.
The team anticipates that, with additional research, their technique will improve GI treatments and research methods.
Some members of the team have been working on ways to use ultrasound to improve drug delivery for 30 years, working mostly with skin. The new study is the first to show it may work through the GI tract.
The following video from MIT demonstrates how the technique works and what the researchers hope it will achieve:
Samir Mitragotri, a professor of systems biology and bioengineering at the University of California-Santa Barbara, carries out research on drug delivery, but he was not involved in the new study. He says the study is a good demonstration of what ultrasound can do, and:
"This technology has great utility in localized as well as systemic delivery of drugs."
Dr. Traverso says that ultrasound may also be a way to improve delivery of drugs to treat cancer and infection in the GI tract. The team is now conducting further animal studies to optimize the technique and prepare it for human trials.
Meanwhile, from another study published in Science Translational Medicine earlier this year, Medical News Today has learned that hydrogel shows promise as a treatment for inflammatory bowel disease because it can be used to precisely target and deliver drugs to affected tissue. The researchers found that it is possible to get hydrogel to stick to targeted sites of inflammation in the colon and slowly release a drug payload over time.