Better than a needle in the eye: new medical device offers hope and relief for patients

[img_inline align=”right” src=”http://padnws01.mcmaster.ca/images/microneedlecloseup.jpg” caption=”A close-up photo of the microneedles found on the surface of a new McMaster-developed device that can deliver drugs to the back of the eye. The device could offer more effective treatment while sparing patients the excruciating routine of having drugs injected directly into their eyes via syringe every six to eight weeks.”]Researchers at McMaster have developed a new system for delivering drugs to the back
of the eye – one that could offer more effective treatment while sparing patients with
vision-related diseases the excruciating routine of having drugs injected into their eyes
by syringe every six to eight weeks.

Instead, the new system could deliver medicine painlessly to the back of the eye
through a flexible patch that would typically stay on the eye behind the lens for as much
as a year at a time, slowly releasing controlled doses of medicine to the vitreous body of
the eye through a group of “microneedles” too small to feel.

The rubbery patch is designed to conform to the eye's contour and the needles can be
tailored to reach specific layers of the eye as needed. The patch would be attached on
an in-patient basis and would not affect the patient's eyesight when in use.

The team of chemical and mechanical engineers tested the system successfully on eyes
extracted from cows, moving the concept a major step closer to being tested on
humans. The innovation is described in an article in the online edition of the Journal of
Biomaterials Applications.

The patch can be compared to medication patches used on the skin, but on a much
smaller scale and using different materials adapted to the complex environment of the
eye.

Such a patch would be a much more precise and effective vehicle for delivering
medications to patients with such conditions as vision-related complications of diabetes
and age-related macular degeneration, both of which are becoming more prevalent.

“There's lots of potential for treating eye diseases that we didn't have even five years
ago. It's really exciting,” said the study's co-author, Heather Sheardown, a professor of
chemical engineering. “There are medications out there to treat these diseases. As we
develop better delivery methods, blindness isn't going to be something that has to
happen. If we can catch the disease early and we can treat it early, we can stop its
progression.”

Sheardown's lab, which focuses on delivering drugs to the back of the eye, will turn next
to developing a reservoir system to allow drugs in such patches to be replenished
externally.

The technical challenge for the team that developed the patch device was not only to
find a way to deliver drugs in such a challenging setting, but to use affordable materials
so the system can compete with hypodermic needles, explained co-author Ravi
Selvaganapathy, an associate professor of mechanical engineering.

“All these stringent requirements were daunting. But the design solution that emerged
was elegant,” he said.

The researchers received funding from the Natural Sciences and Engineering Research
Council of Canada.