Tuesday, 12 June 2012

Device may inject a variety of drugs without using needles


MIT researchers have engineered a device that delivers a tiny, high-pressure jet of medicine through the skin without the use of a hypodermic needle. 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. 

The design is built around 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, 240 m/s) out through the ampoule’s nozzle which is as wide as a mosquito’s proboscis. As the nozzle is so small, the breach in the skin is much less painful. The device can produce up to 100 mega pascals in as short a time as 1 millisecond.

This new system is better than current jet-injection systems as it can inject a wide range of volumes of drugs and at a wide range of speeds, as opposed to current systems which can only release the same amount of drug to the same depth every time. This means that the new system can be viable to use on a broader range of patients, such as children where less pressure is needed to breach the skin. With the ability to change the pressure on demand, it can be changed partway through the procedure allowing trans-dermal injections to be injected to the correct depth, i.e a high pressure to successfully breach the skin before dropping to a lower pressure to release the drug at the desired depth.

The team is also developing a version of the device for transdermal delivery of drugs ordinarily found in powdered form by programming the device to vibrate, turning powder into a “fluidized” form that can be delivered through the skin much like a liquid. Hunter says that such a powder-delivery vehicle may help solve what’s known as the “cold-chain” problem: Vaccines delivered to developing countries need to be refrigerated if they are in liquid form. Often, coolers break down, spoiling whole batches of vaccines. Instead, Hunter says a vaccine that can be administered in powder form requires no cooling, avoiding the cold-chain problem.

Article published May 24, 2012 by MIT News

- The main difference between this new system of jet injector and currently available injectors is the high degree of customization which can lead to the tailoring of injection to a much more personal level.

- Another model of the same device is being developed that can vibrate, causing powders to behave like a fluid and to become viable for injection. This can solve the "cold-chain" problem in developing countries, where liquid vaccines must be refrigerated. As coolers break down, whole batches of vaccines are spoiled. If the vaccine is available in powdered form, no cooling is necessary, avoiding the cold-chain problem.

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