Eye Patch Uses Microneedles for Ocular Drug DeliveryS. Himmelstein | November 26, 2018
Current methods for treating eye diseases, such as glaucoma and macular degeneration, rely on eye drops and ointments, but their efficacy is hindered by the eye’s natural defenses -- blinking and tears. Eye injections can be painful and increase the risk of infection and eye damage.
An eye patch bristling with drug-delivering microneedles is under development as a more effective localized therapy for chronic conditions. The proof-of-concept patch, successfully tested by Nanyang Technological University, Singapore (NTU Singapore) scientists in mice, is covered with biodegradable microneedles that deliver drugs into the eye in a controlled release. The patch is gently pressed onto the eye’s surface, much like putting on contact lenses, after which the drug-containing microneedles detach by themselves and remain in the cornea as drugs are released over time as they dissolve.
When tested on mice with corneal vascularization, a single application of the patch was 90% more effective in alleviating the condition relative to application of a single eye drop with 10 times more drug content. No puncture was observed on the cornea after a week, suggesting that the microneedles are strong enough to penetrate the cornea but not too stiff to spear through the whole cornea.
The 2 mm x 2 mm flexible polymeric eye patch includes nine microneedles of pyramidal shape for optimal tissue penetration. Each needle is composed of hyaluronic acid, a substance found in the eye and used often in eye drops, and is thinner than a strand of hair. A modified version of the hyaluronic acid is added to form a second layer of the needle to slow down its degradation rate and ensure a slower release of the drug.
The research is published in Nature Communications.