Drugs jet into the human body with new device
Medical equipment and pharmaceutical companies are funding a research project to develop a device to inject drugs without using needles. A prototype delivers a tiny, high-pressure jet of medicine through the skin without the use of a hypodermic needle. It can be programmed to deliver a range of doses to various depths up to 16 mm—and that would be a first. Current jet-injection systems can’t do that.
One of the major benefits is the potential to eliminate needle-stick injuries. According to the Centers for Disease Control, accidental needle pricks affect health care workers 385,000 times annually. Another benefit is a higher inoculation rate.
“If you are afraid of needles and have to frequently self-inject, compliance can be an issue,” said Catherine Hogan, a research scientist in MIT’s Department of Mechanical Engineering and a member of the research team. “We think this kind of technology gets around some of the phobias that people may have about needles.”
The big breakthrough is delivery of doses to variable depths in a highly controlled manner.
The design is built around something called a Lorentz-force actuator, which is a powerful magnet surrounded by a coil of wire that’s attached to a piston inside a drug ampoule. When current is applied, a magnetic field produces a force that pushes the piston forward, ejecting the drug at high pressure and velocity (almost the speed of sound in air) through the ampoule’s nozzle. The opening as about as wide as a mosquito’s proboscis.
Andrew Taberner, senior research fellow at the Auckland Bioengineering Institute in New Zealand, told PlasticsToday that “injection rate is controlled by sensing and tightly regulating the motion of the coil using high-speed electronic circuits.” The Auckland Bioengineering Institute and the University of Auckland, participated in the project, which was led by MIT.
The MIT research team generated pressure profiles that modulate the current. The resulting waveforms consist of two phases. The first is a high-pressure phase in which the device ejects drug at a high-enough velocity to penetrate the skin and to the desired depth. The second is a lower-pressure phase in which the drug is delivered in a slow stream that can be absorbed by surrounding tissue. The technology can accommodate different skin thickness and toughness.
“If I’m breaching a baby’s skin to deliver vaccine, I won’t need as much pressure as I would need to breach my skin,” Hogan says. “We can tailor the pressure profile to be able to do that, and that’s the beauty of this device.”
Plastics will play an important role in the device, which is still several years from commercialization.
“It’s likely that the disposable ampoule will be constructed of polycarbonate or similar plastic,” Taberner told PlasticsToday.