Long-lasting drug delivery system may help decrease the spread of malaria

Science Highlights
April 18, 2017
Jessica Meade

New system lasts for up to two weeks in pigs

A photo of a hand holding the capsule with the drug delivery system inside and a photo of the star-shaped structure released in the stomach.
The capsule on the left can be ingested and once it is in the stomach, the outer capsule dissolves, releasing the star-shaped drug delivery system. Credit: Robert Langer, Massachusetts Institute of Technology.
Malaria affects hundreds of millions of people every year, killing more than half a million. Part of the difficulty of eliminating malaria stems from the fact that a large portion of the at-risk population lives in rural areas where access to doctors can be a challenge. This means that many patients often do not comply with the strict daily schedule malaria prevention medicines require. Researchers funded by the National Institute of Biomedical Imaging and Bioengineering (NIBIB) at Massachusetts Institute of Technology (MIT) have developed a capsule that, when dissolved in the stomach, releases a star-shaped material containing drugs that help to prevent malaria infections and lasts for up to two weeks. 
A series of four photos showing the disintegration of the new drug delivery system over the course of two weeks.
Over the course of two weeks, the drug delivery system disintegrates without causing blockages and while continuing to release proper dosages of the drug. Credit: Robert Langer, Massachusetts Institute of Technology.
Ivermectin is a drug that is non-toxic to humans, but will kill malaria-transmitting mosquitoes when the insects ingest blood that contains the drug. It is used to help decrease the spread of malaria in high-risk areas by decreasing the mosquito population and preventing others from being infected. However, in order to be effective, a strict schedule must be followed, which can be difficult for patients in high-risk, low-resource areas.
Robert Langer, Ph.D., and his team at MIT have developed a new drug delivery system that may someday eliminate the need to take ivermectin medication daily. Most pills dissolve in the stomach, releasing the drugs they contain and passing out of the body. However, the structure that is released from the capsule Langer’s team has created can stay in the stomach for up to two weeks, releasing a steady dose of ivermectin. 
The star-shaped material is resistant to gastric acids and large enough that it will not be able to pass out of the stomach until the links creating the star shape dissolve; then it passes harmlessly through the digestive tract. The shape also provides the benefit that it will not block the normal function of the digestive system.
A diagram of the process of how the pill unfolds in the stomach.
This diagram shows how the system is folded into the capsule and how it unfolds once inside the stomach. Credit: Robert Langer, Massachusetts Institute of Technology.
The mathematical models run by the team found that if those currently taking ivermectin with conventional pills were to instead take the drug through this new delivery system, the instances of malaria infection would significantly decrease after two years. 
“This drug delivery system is the kind of low-cost solution that could have a great impact on the spread and destructiveness of malaria,” said David Rampulla, Ph.D., director of the NIBIB program in Delivery Systems and Devices for Drugs and Biologics. 
The technology was tested in a swine model and was shown to be effective for up to fourteen days. Langer and his team hope that in the future it could be made to be effective for an even longer amount of time as well as dispense other kinds of medications. 
This work was supported by the National Institute of Biomedical Imaging and Bioengineering through grant #EB-000244.

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