Infusion pumps can be programmed to deliver drugs at very precise dosages and delivery rates. These pumps may have a feedback device that controls drug delivery according to need. With further development of electronics and miniaturization of pumps and sensors, we'll be able to monitor various vital signs, and that will lead to feedback systems. Such a feedback system could monitor blood glucose levels and deliver insulin when needed. Amidon explains that the size of the pump depends on the amount of drug and the intended length of treatment.
Some pumps are portable, some wearable.
For miniaturized, implantable pumps, methods will have to be devised to refill the device externally, perhaps once a month or once a year, through a catheter. To solve problems like drug tolerance, we're going to have to develop drug delivery programs that are not constant, but programmed with time or circadian doses. We're going to see more complicated therapy in order to be able to reduce the amount of drug exposure and increase its efficacy. If Amidon's vision is to become reality, several technological roadblocks will have to be solved first. Donald Marlowe, director of FDA's division of mechanics and material science, points out just one, as an example.