Filarial worm that causes river blindness

Imagine swallowing a pill designed to release a daily dose of medication for an entire week, month, or even longer. That idea may soon be a reality; HMS investigators at Brigham and Women’s Hospital together with colleagues at MIT have developed just such a drug-delivery capsule. Their report appears in the November 16, 2016, issue of Science Translational Medicine.

The researchers developed a prototype that is about the size of a fish-oil capsule. Once inside the stomach, the capsule unfolds into a star-shaped structure. Although the size of the device prevents it from passing through the pylorus and exiting the stomach, it will allow food to pass through the digestive system.

The team used both mathematical and animal models to investigate the effects of using the capsule to deliver a sustained therapeutic dose of ivermectin, which is used to treat parasitic infections such as river blindness and has been found to keep malaria-carrying mosquito populations at bay. The team found that in large-animal models the capsule remained in the stomach and slowly released the drug for up to 14 days.

“The gastrointestinal tract is a strong, durable passageway through the body,” says C. Giovanni Traverso, an HMS instructor of medicine, gastroenterologist and biomedical engineer at Brigham and Women’s, and co-corresponding author of the study. “We designed the capsule to pause its transit in the stomach to allow for more controlled drug delivery and absorption before passing harmlessly through the gastrointestinal tract.”

The capsule contains polymers and other materials mixed with ivermectin to allow the drug to slowly diffuse over time. The team saw evidence of diffusion for up to two weeks and is interested in further developing the device so that it can dispense a drug for one month or longer.

The research was spurred by the promise of eradicating malaria and the problem of medication nonadherence. It can be difficult to remember to take medications when prescribed, so it’s not uncommon for patients to stop following their medication plans. In this country alone, medication nonadherence is estimated to lead to roughly $100 billion in medication-related hospital admissions annually.

Image: James Cavallini/Science Source

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