无线芯片传递治疗药物

Researchers have tested an implantable device that releases daily dosages of osteoporosis medicine.

The device may one day be a cost-effective alternative to daily injections, and could help manage other diseases as well.

Osteoporosis is a common condition of older people, especially women, in which bones become weak and brittle, and can break easily.

There are medicines to treat osteoporosis. One kind, known as parathyroid hormone, requires daily injections for two years.

But having to give yourself a shot every day, plus the lack of tangible improvement in the patient's condition, results in what researchers call poor compliance.

"And as a result, only 25 percent of the patients will go through the entire 24 months of treatment," says Robert Farra, president of MicroCHIPS, a medical device maker that developed the implantable drug delivery system.

It's only a few centimeters long, and includes up to 365 tiny compartments, each with a single dose of medicine. At the beginning of treatment, the device is inserted under the patient's skin.

"For osteoporosis, the physician will program the device, and the device has the ability to release a dose at a given time, every single day. For other diseases, where the physician may want to alter the dosing schedule, they will have the ability to wirelessly reprogram that dosing schedule," Farra says.

The injectable form of the parathyroid hormone is a liquid that has to be refrigerated, but for the implantable device, the researchers developed a powered version that remains effective when sealed in its tiny compartment for as long as a year.

The device itself can be implanted in a doctor's office with local anesthetic.

Farra and his colleagues say safety tests of a small, 20-dose prototype unit were successful, and they are now designing a 365-dose version.

"We anticipate two years to complete the design, and then we may be required to do two additional trials, taking us out to a total of four years before the device is available on the commercial scale."

The price of the device is speculative, but Farra says the cost should be similar to the current regimen of daily injections.