Scientists help drug delivery to the eye become less painful
By using different types and sizes of peptide-based nanoparticles and nanocapsules as the drug carrier
Age-related macular degeneration (AMD) currently affects 6.5 million Europeans. One way to treat this condition is by delivering drugs direct to the source by injecting them into the back of the eye. At present this procedure may involve many injections and can be very uncomfortable for the patient, but a consortium of European scientists may have found a solution.
Professor Neil Cameron of the University of Durham in the UK has created a system that uses peptides that are capable of assembling themselves into nanoparticles. These biodegradable and biocompatible materials can be used as containers for therapeutic molecules, which can then be delivered to the desired area and released in a controlled manner.
Cameron says the particles are around 1,000 times thinner than a human hair, which means they are able to pass through the sub-conjuctival and sub-tenon routes into the eye that are less traumatic for the patient.
As well as AMD, which occurs when cells in the highly sensitive area of the retina known as the macula become gradually damaged causing loss of central vision, there are a number of other conditions that require drug delivery to the retina through an injection to the back of the eyeball – at present, the only method for delivering these drugs. Cameron and his colleagues believe their system might be able to provide a less distressing alternative.
We can make a few different types and sizes of particles
This type of drug-delivery system has other advantages; one being that the release of the drug is controlled. Peptides are commonly found in the body, and so endogenous enzymes naturally break them down. Thus, when the peptide-based micro- and nanoparticles containing the drugs are inserted into the eye, they biodegrade and release the drug slowly by diffusion. This gives them an advantage over drugs administered straight into the bloodstream, which have a harder time reaching the eye due to the blood-retinal barrier.
Cameron and his colleagues created a consortium of experts including materials scientists and biochemists to put this system into action. The PANOPTES project has focused on creating methodologies for the industrial manufacture of novel peptide-based nanoparticles and nanocapsules for sustained drug delivery to the back of the eye.
The project has involved research groups from three European universities and all three have had success in producing nanoparticles.
'We can make a few different types and sizes of particles,' says Cameron. 'Some of them have solid cores, whereas others are more like little capsules, and we have successfully loaded each of them with a number of relevant drugs. The materials have been extensively tested in vitro, and we have also carried out some in vivo testing.'
The aim of PANOPTES has been to refine at least one drug delivery system and bring it to the point where it is ready for clinical trials and this looks likely, although exact results cannot be disclosed at present due to commercial interests, said Cameron.
