Microfluidic device for controlled ocular drug delivery

Proper drug concentration in the treatment of ocular disease is challenging. To alleviate this, we developed a 10 × 5 mm2 device for controlled delivery of drugs to the eye consisting of a 320 µm) hyaluronic acid (HA) laden hydrogel covered on one side by monolayer of graphene. The hydrogel composition contains HA due to its lubricating and wound healing properties, biocompatibility and safety. The HA was tested at 0.5, 1, and 2 percent w/v. Graphene was added to allow slow release of the active component and to act as an impermeable layer. As part of a proof-of-concept study, inserts were tested in vivo on a healthy dog after the owner provided written informed consent. They were inserted in the cul-de-sac of one eye with the graphene layer facing the outer eyelid and the hydrogel remaining in contact with the conjunctiva and lower cornea. The results show only a slight increase in clinical signs of conjunctivitis in the last two trials, while the patient did not experience any visible discomfort. In the first two trials, the insert remained in the cul-de-sac for almost 6 hours before being expelled, with the last trial lasting longer than 1 hour. The inserts were found to be well tolerated, but in terms of biofunctionality, further studies are needed to increase the residence time and to further optimise the shape and positioning of the device. The clinical use of the device is anticipated to have a positive impact on the lives of patients afflicted by dry eye disease.