Dissolving ‘contact lens’ new drug delivery platform?
A long-sought alternative to topical eye drops could come in the form of a proposed dissolving nanowafer that might help increase both patient compliance and measured drug delivery.
"It's been a challenging nut to crack to release medications in a controlled way."
Recently published in the journal ACS Nano, research from the Baylor College of Medicine detailed plans for a slow-release drug dispersal polymer—about one-twentieth the thickness of a contact lens—that sits on the sclera and dissolves with time.
Termed a nanowafer drug delivery system by researchers, the transparent disc is made of polyvinyl alcohol resin with tiny drug-laden reservoirs and slowly dissolves while maintaining a high concentration of medication in the tear film, in theory, providing better efficacy over eye drops.
Animal models were used to test the nanowafers in delivering medication for corneal neovascularization and found a once-daily nanowafer treatment had almost twice the efficacy compared to twice-daily eye drops.
Researchers are now looking at adapting the system for cystinosis and other eye injuries with clinical trials expected in the next year. There's no timetable for nanowafers entering the market.
Potential for greater compliance with self-administered meds?
Doctors know all too well the weak link in self-administered medication is patient compliance when it comes to eye conditions where prescription eye drops are the primary treatment course.
According to a 2008 report in the Canadian Journal of Ophthalmology, of the 500 glaucoma patients tracked in the study:
- 25 percent reported missing at least one eye drop weekly, mainly due to forgetfulness
- 7 percent reported missing their eye when administering drops
- 34 percent demonstrated improper application technique
Furthermore, eye drops aren't ideal for measured applications. Thomas Quinn, O.D., AOA Contact Lens and Cornea Section chair, told AOA Focus in the award-winning July/August feature article 'Get Smart: Contact Lenses of the Future, Today,' that drug concentration spikes in the tear film after drop placement, but declines with each blink and may reach a period with no effective medication occurring at all.
Discussing the nanowafer research, Dr. Quinn says he has initial concerns for how the vision is impacted once the nanowafers begin dissolving, and whether or not the particles break into larger pieces upon dissolving. That being said, the research proves exciting.
"We've been working on contact lenses to deliver medications to the eye for a long time, and it's been a challenging nut to crack to release medications in a controlled way," he says.