Monthly medicine: Capsule developed for continuous release of medicine

A long-acting drug delivery capsule has been developed that can continuously release a dose of medicine for up to two weeks.

Researchers from Brigham and Women’s Hospital, alongside the Massachusetts Institute of Technology developed the capsule in an effort to help medication adherence.

Co-corresponding author C. Giovanni Traverso said: "We want to make it as easy as possible for people to take their medications over a sustained period of time. When patients have to remember to take a drug every day or multiple times a day, we start to see less and less adherence to the regimen. Being able to swallow a capsule once a week or once a month could change the way we think about delivering medications,"

To test the capsule’s real-world applications, the team used mathematical modelling and animal models to examine the effects of delivering a continuous dose of ivermectin, a drug used to treat parasitic infections. The researchers found that in large animal models, the capsule safely stayed in the stomach, releasing a dose for 14 days.

The capsule is about the size of a fish oil capsule when swallowed. When in the stomach, the capsule unfolds into a star-shaped structure which is too large to exit the stomach but still allows food to pass through the digestive system.

"The gastrointestinal tract is a strong, durable passage way through the body. We designed the capsule to pause its transit in the stomach to allow for more controlled drug delivery and absorption, before passing through the GI tract without any harm," said Traverso. "Some of the challenges we face in getting the capsule in place are the 'ship in the bottle problem' -- in this case, the neck of the bottle is the oesophagus -- and preventing the capsule from passing through the rest of the tube. The pylorus is about two centimetres in diameter so we designed our system to be four centimetres when it opens." 

The capsule contains polymers and other materials mixed with ivermectin to allow the drug to slowly diffuse out of the material over time. The team is looking to develop the system to provide a continuous dosage for one month or longer.

Co-first Andrew Bellinger said: "In addition to improving adherence, our ultra long-acting drug delivery system may reduce side effects and improve drug efficacy by smoothing out the high variability of serum concentration that often comes with taking a daily pill.”