(RxWiki News) Delivering injected medication to the back of the eye for conditions such as age-related macular degeneration (AMD), the leading cause of blindness among older adults, can be challenging for doctors.
Researchers may have found a better way for directly injecting medication into the back of the eye.
They have successfully demonstrated that micro-needles of less than a millimeter in length can deliver drug molecules and particles to an animal model.
"Get regular eye exams to identify vision loss early."
Samirkumar Patel, PhD, lead author, a postdoctoral researcher at the Georgia Institute of Technology and director of research for Clearside Biomedical, said that the findings could lead to a simple and safe procedure, giving doctors a better way to target drugs to specific locations in the eye.
Researchers believe that the smaller needles will cause less trauma to the eye, while also reducing the risk of infection.
The minimally-invasive technique may offer an improvement over conventional methods often involving injections into the center of the eye. The micro-needles can be used to target the suprachoroidal space of the eye, a passageway for injected drugs to travel across the sclera, or white portion of the eye. Medication then travels along the eye's inner surface to the back of the eye.
During the pre-clinical study, investigators used the stainless steel micro-needles to inject fluorescent compounds into an animal model. Once injected, researchers observed that the compounds glowed inside the eye.
Researchers have only attempted injecting compounds. The next step will be a study to examine whether the micro-needles can successfully transport drugs to the eye.
Investigators also found found that particles that reached the suprachoroidal space remained there for an extended amount of time, suggesting that the it could accommodate a variety of drugs, possibly including time-release injected medications.
The molecules and particles do not meaningfully reach the lens or front part of the eye, where drug side effects tend to occur. If confirmed, this could allow patients with chronic eye diseases to receive fewer injections.
"The study showed that if we inject non-degradable particles into the suprachoroidal space and wait as long as two months, the particles remain," said Mark Prausnitz, a Regents professor in Georgia Tech's School of Chemical and Biomolecular Engineering.
"That means there is no natural mechanism to remove the particles from the eye. Knowing this, we can design biodegradable particles with drugs encapsulated in them that can slowly release those drugs over a period of time that we could control."
Dr. Christopher Quinn, an optometrist with Omni Eye Associates, noted that new medications for retinal diseases have allowed doctors to better treat these eye conditions.
However, delivering these medications can be challenging because the eye does not readily allow drugs to easily pass from blood vessels into the retina.
"This has meant that direct injection of medication into the back of the eye has been the most effective method to deliver these medications," said Dr. Quinn. "New techniques like microneedles or jet injections minimize the trauma associated with traditional injections into the eye and will be a welcome advance in the delivery of medication where it is most needed."
The study, funded by the National Eye Institute and Research to Prevent Blindness, was recently published in the July issue of the journal Investigative Ophthalmology & Visual Science.