Scientists have developed a new star-shaped drug delivery capsule that remains in the stomach for up to two weeks after being swallowed, gradually releasing medication. This type of drug delivery could replace the need for repeated doses, which would help to overcome one of the major obstacles to treating and potentially eliminating diseases such as malaria.
Researchers at Massachusetts Institute of Technology (MIT) and Brigham and Women’s Hospital in the USA used this approach to deliver a drug called ivermectin, which they believe could aid in efforts to eliminate malaria. However, this approach could be applicable to many other diseases, says Robert Langer, the David H. Koch Institute Professor at MIT and a member of MIT’s Koch Institute for Integrative Cancer Research.
“Until now, oral drugs would almost never last for more than a day,” Professor Langer says. “This really opens the door to ultra-long-lasting oral systems, which could have an effect on all kinds of diseases, such as Alzheimer’s or mental health disorders. There are a lot of exciting things this could someday enable.”
Long-term delivery
Drugs taken orally tend to work for a limited time because they pass rapidly through the body and are exposed to harsh environments in the stomach and intestines. Professor Langer’s laboratory has been working for several years to overcome this challenge, with an initial focus on malaria and ivermectin, which kills any mosquito that bites a person who is taking the drug. This can greatly reduce the transmission of malaria and other mosquito-borne illnesses.
To achieve ultra-long-term delivery, drugs need to be packaged in a capsule that is stable enough to survive the harsh environment of the stomach and can release its contents over time. Once the drug is released, the capsule must break down and pass safely through the digestive tract.
Working with those criteria in mind, the team designed a star-shaped structure with six arms that can be folded inward and encased in a smooth capsule. Drug molecules are loaded into the arms, which are made of a rigid polymer called polycaprolactone. Each arm is attached to a rubber-like core by a linker that is designed to eventually break down.
After the capsule is swallowed, acid in the stomach dissolves the outer layer of the capsule, allowing the six arms to unfold. Once the star expands, it is large enough to stay in the stomach and resist the forces that would normally push an object further down the digestive tract. However, it is not large enough to cause any harmful blockage of the digestive tract.
The research has led to the launching of Lyndra, a Cambridge-based company that is developing the technology with a focus on diseases for which patients would benefit the most from sustained drug delivery, including neuropsychiatric disorders, HIV, diabetes, and epilepsy.
The study is published in Science Translational Medicine.