Microelectronic control of drug delivery.

Microelectronic control of drug delivery devices enables precise management of drug delivery profiles. Iontophoresis patches offer microelectronic control over delivery in a noninvasive manner, but these are limited to the administration of relatively small molecules at small doses. Infusion pumps are widely used for delivery of insulin and other drugs; however, they require an invasive catheter that many patients find inconvenient and can be a site of infection. Implanted pumps avoid these problems, but they require long-term commitment associated with surgical implantation. An alternative is an implanted microchip containing many protected reservoirs filled with drug powder that is selectively released under microelectronic control. This device offers the promise of long-term drug stability in the solid state and precise digital drug dosing. Building on more than 10 years of preclinical studies, this wirelessly controlled microchip technology recently underwent a first-in-human clinical study. The microchip was implanted subcutaneously in the abdomen of eight female patients with osteoporosis. A remote operator was able to establish a wireless link with the microchip to program the schedule of human parathyroid hormone dosing from the device. This study showed that the wireless microchips produced pharmacokinetics similar to those from subcutaneous injections of the drug and produced less variable drug levels in the blood. There were also no toxic or adverse events due to the microchip or drug. This study represents an important step towards more widespread use of microelectronic control of drug delivery to improve pharmaceutical therapies.