Eye drops with Turmeric-derivative may be new treatment of glaucoma

Researchers of UCL and Imperial College London have found a derivative of turmeric that could be used in eye drops to treat the early stages of glaucoma. The study was published in the journal Scientific Reports.

Curcumin, which is the active ingredient of turmeric can now be delivered directly to the back of the eye using eye drops by a new method developed by the researchers. This will overcome the poor bioavailability and solubility of curcumin.

The study found that the eye drops can reduce the loss of retinal cells in rats, which is considered to be an early sign of glaucoma.

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A glaucoma is a group of eye conditions affecting more than 60 million people worldwide that leads to irreversible blindness in 10% of the cases. What happens in Glaucoma is that there is a loss of retinal ganglion cells, a type of neuron located near the surface of the retina. There is no treatment so far to stop this early loss.

"Curcumin is an exciting compound that has shown promise at detecting and treating the neurodegeneration implicated in numerous eye and brain conditions from glaucoma to Alzheimer's disease, so being able to administer it easily in eye drops may end up helping millions of people," said the study's lead author, Professor Francesca Cordeiro.

Previous studies have shown the efficacy of curcumin in protecting retinal ganglion cells when administered orally. For the current study, the researchers were seeking to find a more reliable method to deliver curcumin. As curcumin has poor solubility, so it does not easily dissolve and get absorbed into the bloodstream, so the oral administration would require people to take large amounts of tablets (up to 24 a day) that may cause gastrointestinal side effects.

The team developed a novel nanocarrier, wherein the curcumin is contained within a surfactant combined with a stabilizer, both of which are known to be safe for human use and are already in existing eye products. The nanocarrier can be used in eye drops to deliver much higher loads of curcumin than other products in development, increasing the drug's solubility by a factor of almost 400,000, and localizes the curcumin in the eyes instead of throughout the body.

Professor Cordeiro added: "As we live longer, diseases such as glaucoma and Alzheimer's are steadily increasing. We believe our findings could make a major contribution to helping the lives of people affected by these devastating diseases."

The researchers initially tested the product on cells that are used to model glaucoma, before conducting trials in rats with eye conditions involving the loss of retinal ganglion cells.

The retinal ganglion cell loss was significantly reduced compared to matched controls after the eye drops were used twice-daily in the rats for three weeks, and the treatment was found to be well-tolerated with no signs of eye irritation or inflammation.

The researchers after finding an effective way to deliver curcumin, are hopeful that curcumin could also be used to diagnose Alzheimer's disease, as it can bind to the amyloid beta protein deposits implicated in Alzheimer's, and can be detected in the retina with fluorescence to highlight the malignant proteins.

"We are now researching diagnostic uses for these eye drops alongside other ways to visualize the retina, as eye tests can be an opportunity to detect signs of neurodegeneration with a simple, non-invasive test," said co-lead author Dr. Ben Davis.

For reference log on to http://10.1038/s41598-018-29393-8