Newly patented microneedle for ocular drug delivery
A goal of ophthalmology researchers is to deliver medication to the back of the eye in a selective and minimally invasive way. Scientist Henry F. Edelhauser and two fellow researchers have recently been awarded a U.S. patent for application of microneedle technology, designed to do just that.
Filed for in 2007 and awarded in April 2011, the patent (US 7,918,814) was awarded to Edelhauser, our former director of research, along with Mark Prausnitz, professor of chemical and biomedical engineering at the Georgia Institute of Technology, and Ninghao Jiang, a research graduate student at Georgia Tech, now employed at CNA, a non-profit research organization in Virginia.
Because the microneedle apparatus is so much smaller than currently used intravitreal needles, there may be less discomfort for the patients. Many patients with age-related macular degeneration have injections on a regular basis. In the future, the same microneedle technology may be used to inject medication directly into the eye for many other ocular conditions, such as glaucoma, eliminating the need to put drops in the eyes every day—a real chore for some patients.
"The beauty of this hollow-tubed microneedle is that it can serve as a route for targeted drug delivery for retinal disease using an array of delivery suspensions such as microbeads and microbubbles," says Edelhauser.
"Moreover, a sustained delivery can be achieved with proper formulation design. In the future, this new process should be helpful in the treatment of several ocular diseases."
and a book…
Edelhauser also has a new textbook, Drug Product Development for the Back of the Eye (aapspress/Springer), edited by Eye Center researcher Edelhauser and Uday B. Kompella, of the University of Colorado, explores approaches for a delivery system to get drugs to the back of the eye. In the past, drug delivery was typically systemic and not targeted to where it might do the most good for the particular ophthalmic disease and disorder.
The book explores tissue isolation, drug analysis, non-invasive approaches to drug delivery and nontechnology-based products, such as microneedles. Additionally, it offers approaches to assess and model pharmacokinetics of the eye noninvasively, as well as coverage of transscleral drug delivery.
In 2006 Edelhauser and other co-principal investigators received an R-24 grant for five years, for a total of $6M, only the third R-24 grant awarded by the NEI, part of the NIH, at that time. The research involved drug delivery to the posterior segment of the eye. The goal was to find an alternative to intravitreal injections, focusing on a transscleral approach.
Principal methods up to that point to deliver medicine into the eye included eye drops, systemic (oral medicine) processes or injections. Disadvantages to these methods included drug dilution, systemic side effects and injection-associated risks. Tissue-specific transport of the drug could more safely and efficiently deliver the drugs to the retina, for example.
"Dr. Edelhauser has become the world's authority on transscleral drug delivery," says Eye Center director Timothy W. Olsen. "This text has brought together the leading thinkers and strategic scientists in pharmacotherapy to the eye and will provide a firm data-based foundation that frames the science in this burgeoning field—a field that is likely to grow and expand exponentially."