CHICAGO (Reuters) - An implantable, wireless microchip delivered osteoporosis medicine to a small group of Danish women, raising hope for a new kind of drug delivery device that might allow patients to skip regular injections, U.S. researchers said on Thursday.

The device, now being developed by privately held Microchips Inc, has a wireless receiver that signals the microchip to release the drug.

"Until now, you never had any way you could do this," said Dr. Robert Langer of the Massachusetts Institutes of Technology, who helped to develop the technology and is a board member of Microchips Inc.

Langer said the device could be used for different types of injectable drugs where getting people to take their medications regularly is a problem.

That is often the case in patients with severe osteoporosis, who tend to skip doses of their medications because they cannot tell whether or not the injections are affecting the density of their bones.

That is something the microchip was designed to overcome, said Robert Farra of Massachusetts-based Microchips, which paid for the study. Farra, Langer and colleagues published a paper on the study in Science Translational Medicine.

Instead of constantly releasing small amounts of drug, like most drug-delivery systems, the microchip releases medication on command all at once, much like an injection would.

It can be activated by telephone or computer using a special radiofrequency reserved for medical use to safeguard against accidental release of the drug, Langer said.

GOLD NANOPARTICLES

The microchip itself is a thin wafer, about the size of a small coin, made with tiny wells that hold concentrated doses of medication. These doses are covered with a layer of gold nanoparticles, which dissolve when exposed to a certain radiofrequency. The wafer is implanted under the skin with a receiver device that is roughly the size of a heart pacemaker, Langer said.

In the system's first test in people, the team implanted the device in eight Danish women aged 65 to 70 with a severe form of osteoporosis which required injections of Eli Lilly & Co's hormone treatment teriparatide.

The researchers sent daily signals to the microchip device to release the drug for up to 20 doses. Then, they followed up with a period in which the women took hormone injections.

As seen in animal studies, a fibrous collagen-based membrane developed around the device, but the drug still performed just as well as daily injections in the women, improving bone formation and reducing the risk of fractures, the researchers said.

Still, there were some hitches.

John Watson, a professor of bioengineering at the University of California, San Diego, said in an editorial the device failed to work in one of the patients, and that data was not included in the analysis.

And the team had some manufacturing issues and was able to manufacture only one device with all 20 reservoirs filled with the study drug. Even so, all doses in the microchips were released in the patients, a sign that the device could work in people, Watson said.

"Several years are still needed to bring this technology to approval by the U.S. Food and Drug Administration and to the clinical promise reflected in this small study," Watson wrote.

The current device holds only 20 doses, but Langer said the group is working on adding more doses to the device.

The company hopes to have a version of the device on the market in five years. Langer said he sees potential for other uses, such as treating diabetes or delivering cancer drugs.

SOURCE: http://bit.ly/xUUOwu Science Translational Medicine, February 16, 2012.

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Microchip delivers drug; can it replace shots?