Developing eye drops that can reach the back of the eye

Dr Bridgeen Callan, Ulster University - £91,398

This research aims to see if drugs for wet age-related macular disease (AMD), delivered through eye drops, can make their way to the macula.

This could lead to patients not needing frequent injections.

What was the problem?

Wet AMD is treatable through drugs referred to as anti-VEGFs, however, these drugs need to be injected into the eyes every month or few months. While these are very safe, there are always potential side effects with injections, and they can be unpleasant, uncomfortable or stressful for patients.

Nanotechnology is the manipulation of materials on an atomic or molecular scale. Using this process this project was aiming to investigate whether wet AMD drugs could be delivered through eye drops. As the drug has to get from the front to the back of the eye, there are many barriers the drugs need to get through.

What did the project achieve?

The team were able to use a nanoparticle called a polymersome (a tiny hollow sphere that encloses a solution) as a vehicle to transport a drug to the back of the eye. Polymersomes are a new focus in science, being more stable, having a longer shelf-life and able to carry drugs with less leakage than liposomes, which have to date been used in injections. The drug is held between two layers which means that it is suitable for hydrophilic and hydrophobic drugs. Loading the polymersome with additional chemical arms such as cholesterol also improves endocytosis (uptake rate into the cell) without reducing the amount of drug carried.

What next?

This project has now applied for a patent before moving into clinical trials and then ultimately fully commercialising the product.

The adaptability of these nanoparticles makes them suitable for delivery of a wide range of drugs, with the delivery of nucleic acid-based therapies perhaps the most exciting.

These polymersomes will not only deliver drugs across the membrane barriers at the back of the eye but also protect their internalised drug cargo from degradation within the eye.

Professor Callan described the project and its findings in more detail at our 2023 Macular Disease Conference. You can watch her talk below.