Diabetic retinopathy is caused by damage to blood vessels of the retina. Almost everyone who has had diabetes for thirty years or more has some sign of the condition. Now, retinopathy researchers have come up with a device that will be implanted behind a patient’s eye to deliver medication on demand. “We wanted to come up with a safe and effective way to help diabetic patients safeguard their sight,” said lead author Mu Chiao, a mechanical engineering associate professor at the University of British Columbia (UBC) in Vancouver, in Science Daily. “This new device offers improvements upon existing implantable devices for drug delivery.”
One of the current treatments is photocoagulation laser therapy, in which tiny burns are made on the retina to seal blood vessels. The side effects may be the loss of peripheral (side) vision or night vision. The other treatment is anti-cancer drugs, but the high dosages required expose other tissues and may damage them.
The UBC team, which also included mechanical engineer Fatemeh Nazly Pirmoradi, PhD, incorporated the ability to trigger the drug delivery system through an external magnetic field. The team sealed the reservoir of the implantable device, which is no larger than the head of a pin, with an elastic magnetic silicone membrane. The magnetic field causes the membrane to change shape in order to discharge a specific amount of the drug, much like squeezing water out of a flexible bottle.
In a series of lab tests, the UBC researchers loaded the implantable device with the drug docetaxel and triggered it to release a dosage suitable for treating diabetic retinopathy. They found that the implantable device worked as it should, with negligible leakage over 35 days.