Scientists have developed a new drug capsule that remains in the stomach for up to two weeks after being swallowed, gradually releasing its payload, paving the way for a long acting pill that may effectively treat malaria and many other diseases.
This type of drug delivery could replace inconvenient regimens that require 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 US used this approach to deliver a drug called ivermectin, which they believe could aid in malaria elimination efforts.
However, this approach could be applicable to many other diseases, said Robert Langer, Professor at MIT. “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,” he said.
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. Langer’s lab 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. The team envisions that long-term delivery of ivermectin could help with malaria elimination campaigns based on mass drug administration – the treatment of an entire population, whether infected or not, in an area where a disease is common.
In this scenario, ivermectin would be paired with the antimalaria drug artemisinin, researchers said. 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 digestive tract.
In tests in pigs, the researchers confirmed that the drug is gradually released over two weeks. The linkers that join the arms to the core then dissolve, allowing the arms to break off. The pieces are small enough that they can pass harmlessly through the digestive tract.
“This is a platform into which you can incorporate any drug. This can be used with any drug that requires frequent dosing. We can replace that dosing with a single administration,” said MIT postdoc Mousa Jafari. The research was published in the journal Science Translational Medicine.