Tiny Needles Reshape Major Eye Disease Treatment

Novel microneedles allow dramatic dose sparing when compared to subconjunctival and topical administration of drugs directly into the eye.

Developed by researchers at the Georgia Institute of Technology (GATech; Atlanta, USA) and Emory University (Atlanta, GA, USA), the microneedles, which range in length from 400 to 700 micrometers, could provide a new way to deliver drugs to specific areas within the eye relevant to glaucoma and corneal neovascularization, two of the world’s leading eye diseases. By targeting the drugs to specific parts of the eye instead of the entire eye, researchers hope to increase effectiveness, limit side effects, and reduce the amount of drug needed.

To treat glaucoma, the stainless steel microneedles were designed to penetrate through the sclera (the outer layer of the eye), to the supraciliary space located near the ciliary body, which produces the aqueous humor. The chosen drug is also formulated with increased viscosity to retain it near the injection site and provide a controlled release of the therapeutic compounds. And because the injection targets drug delivery, just one percent of the amount of drug is required to produce a similar decline, as compared to eye drops.

To treat corneal neovascularization, the researchers took a different approach, coating solid microneedles with Bevacizumab, an antibody-based drug that prevents blood vessel growth. They inserted the coated needles near the point of an injury, keeping them in place for approximately one minute until the drug dissolved into the cornea. In an animal model, placement of Bevacizumab halted growth of unwanted blood vessels for two weeks after just a single application. The study describing the new microneedles was published on November 13, 2014, in Investigative Ophthalmology & Visual Science.

“The power of microneedles for treating eye conditions is the ability to target delivery of the drug within the eye,” said lead author Prof. Mark Prausnitz, PhD, of the school of chemical and biomolecular engineering at GATech. “We are developing different microneedle-based systems that can put the drug precisely into the part of the eye where it’s needed. In many cases, we hope to couple that delivery with a controlled-release formulation that would allow one application to treat a condition for weeks or months.”

Related Links:
Georgia Institute of Technology
Emory University