A device that delivers a tiny, high-pressure jet of medicine through the skin without the use of a hypodermic needle has been developed by MIT researchers. The device can be programmed to deliver a range of doses to various depths- an improvement over similar jet-injection systems that are now commercially available. Among other benefits, the researchers said, the technology may help reduce the potential for needle-stick injuries. A needleless device may also help improve compliance among patients who might otherwise avoid the discomfort of regularly injecting themselves with drugs such as insulin.
The design is built around a mechanism called a Lorentz-force actuator - a small, powerful magnet surrounded by a coil of wire that's attached to a piston inside a drug ampoule. When current is applied, it interacts with the magnetic field to produce a force that pushes the piston forward, ejecting the drug at very high pressure and velocity (almost the speed of sound in air) out through the ampoule's nozzle - an opening as wide
as a mosquito's proboscis.
The speed of the coil and the velocity imparted to the drug can be controlled by the amount of current applied; the MIT team generated pressure profiles that modulate the current. The resulting waveforms generally consist of two distinct phases: an initial high-pressure phase in which the device ejects drug at a high-enough velocity to "breach" the skin and reach the desired depth, then a lower-pressure phase where drug is delivered in a slower stream that can easily be absorbed by the surrounding tissue.
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