Eye diseases like macular degeneration and diabetic retinopathy are among the leading causes of blindness worldwide. The good news is there are several drug therapies that can be used to treat these disorders and prevent a total loss of sight. The bad news is that these therapies require drugs to be delivered to the back of the eyeball with a syringe. Understandably, most people are like me and don't even like the pairing of the words "needle" and "eyeball" in the same sentence. As a result, many patients opt for far less effective treatments. Now a team has found a way to provide this valuable therapy to the back of the eye with topical drops.
Blindness from both macular degeneration and diabetic retinopathy are the result of blood vessels growing out of control behind the eye. The vessels are tamed with drugs that have to be brought to the tissues they are growing in. To avoid having to inject these drugs, researchers speculated that they might be able to make use of a drug-ferrying synthetic polymer with a peptide known as penetratin. They knew that the peptide had good permeability in the eye and speculated that pairing it with the polymer might allow drugs carried in this way to migrate to the rear of the eyeball. The team tested this out on rats and found that the complex rapidly migrated to the rear of their eyeballs in reasonable concentrations. Perhaps more importantly, they found that it stayed in the back of the eyeball for more than eight hours - long enough for the drugs to have their needed effect. This hideously complex research published in Applied Materials and Interfaces and, if you fancy trying to digest the original paper, you can do so here.