The key to a more convenient, less uncomfortable way to deliver injectable drugs could lie in ingredients found not in a high-tech lab but in most people’s kitchens.
Purdue University researchers used a simple solution of sugar, yeast, water and body heat to create a tiny pump they think could someday power a drug delivery patch.
Just 1.5 centimeters in size, the device looks like this: A drug chamber with an output port is separated from a small chamber housing sugar and yeast by a layer of flexible polymer. To activate the pump, water is added to the yeast and sugar chamber, and the device is put on the skin. Body heat sparks fermentation of the yeast and sugar, which produces carbon dioxide gas that pushes against the membrane, forcing the drug out of the port.
In a study recently published in the journal Lab on a Chip, the device demonstrated that it could generate a constant amount of gas for up to 10 hours and could tolerate small variations in skin temperatures.
In a release from the university, professor of electrical, computer and biomedical engineering Babak Ziaie said that this kind of pump could be used in drug delivery patches that use microneedles, enabling the use of disposable patches to deliver a wider range of drugs. Current patches deliver drugs transdermally, he said, so they can only be used with drug made of small molecules that can be absorbed through the skin. And creating a pump that can power a microneedle patch has proven difficult for researchers and companies, he said.
According to Ziaie, the device has other advantages. Yeast, for one, has a long shelf life and can remain dormant at room temperature for several years. Or, the device could also be pre-loaded with a prepared water solution and stored in a refrigerator, since fermentation is temperature-dependent. It would also be easier and affordable to mass produce than a device powered by a battery.
Currently available patch pumps focus insulin delivery, but a number of devices are in development for transdermal or microneedle delivery of other drugs. Ratio Inc.’s device in the works looks fairly similar to Ziaie’s – it uses a swelling polymer, hydrogel, to power a drug delivery pump that uses microneedles to pierce the skin. SteadyMed Therapeutics also just raised $10.4 million to commercialize a self-powered patch pump.
Ziaie and doctoral student Manuel Ochoa, who are based at Purdue’s Birck Nanotechnology Center in the university’s Discovery Park, have filed a provisional patent application for the technology.
[Photo from Purdue University]