Many drugs that would benefit from transdermal delivery are either made of molecules too large to penetrate the skin or are hydrophilic and so don't absorb very well. To overcome these limitations, Purdue University scientists have created a pump to literally push drugs through microneedles of 20 micron diameter. The pump requires no batteries and is activated by pushing your finger against it for about twenty seconds.
The pump contains a liquid that boils at body temperature so that the heat from a finger's touch causes it to rapidly turn to a vapor, exerting enough pressure to force drugs through the microneedles.
The liquid is contained in a pouch separated from the drug by a thin membrane made of a rubberlike polymer, called polydimethylsiloxane, which is used as diaphragms in pumps.
Researchers have filed an application for a provisional patent on the device.
Ziaie has tested prototypes with liquids called fluorocarbons, which are used as refrigerants and also in semiconductor manufacturing.
Press release: New pump created for microneedle drug-delivery patch