Wireless Implant Meters Drug Doses

R. Colin Johnson


• Smart medical implants can now dispense drugs into the bloodstream as a result of wireless signals sent to it from the doctor's office.A thumbnail-sized microchip containing multiple drug reservoirs has now passed clinical trials in which a wireless signal was used to release precise daily doses, instead of requiring patients to inject themselves with the drug. The technology could help patients who require frequent or daily injections.
  Studies have shown that many medical patients do not take their meds on schedule, especially when they are feeling good and think they no longer need them. Unfortunately, many drugs today need to be taken regularly and in precise doses in order to maintain their long-term therapeutic effect. As a result, many new technologies are being tried that prompt the patient, via email or telephone reminders, to administer the drug themselves. Others have tried using smart pills to wirelessly notify the doctor when a specific drug has been taken.
  
  MicroCHIPS has developed an implantable medical device which allows repeated wireless drug delivery in lieu of injections. (Photo courtesy of M. Scott Brauer)
  The new approach that has just passed clinical trials in Denmark uses a smart microchip implant that stores daily doses of drugs, then automatically dispenses them in response to a wireless signal sent by the attending physician on the Medical Implant Communication Service (MICS, frequencies band between 401- and 406-MHz). As a result, patients can receive regular, precise doses of their medicines in perfect compliance with their doctor's instructions.
  "It can be very difficult to get patients to accept a drug regimen where they have to give themselves injections," said MIT professor Michael Cima. "This avoids the compliance issue completely, and points to a future where you have fully automated drug regimens."
  The smart implant is manufactured by MicroChips Inc. under a license from MIT where Cima and fellow professor Robert Langer have been developing the idea for several years. Now that the clinical trials have been successful, the company is increasing the number of doses each chip contains as well as creating a variety of different sized reservoirs so that all the different drugs a patient takes can be held by a single smart implant.
  "You can deliver multiple drugs [using] remote control," said Langer. "You could literally have a pharmacy on a chip."
  The successful clinical trials showed no adverse side effects, but in fact showed a significant improvement in the accuracy and timing of the doses given, compared to depending on patients to administer the drugs themselves. The trials administered a drug for osteoporosis, but any patient with chronic diseases, regular pain-management, or other drugs that need to be taken daily could benefit from the implant.
  The smart implant can be injected under the skin in the doctor's office in about 30 minutes using a local anesthetic and lasts about four months before needing to be replaced. Each dose is held in a reservoir capped with platinum/titanium which melts when it receives a signal using the MICS wireless network protocol. The test chips only held 20 doses, but the production models now in development will hold hundreds of doses. Eventually MicroChips plans to develop even smarter models that can administer drugs in response to on-chip sensors, such as a glucose sensor for diabetics.