Patch delivers drugs to eye

Efficient delivery of drugs to the eye can be challenging. It requires either high systemic doses or frequent topical doses. A team led by Peng Chen, Xiaomeng Wang, and Chenjie Xu of Nanyang Technological University reports a flexible eye patch with detachable microneedles that easily delivers drugs to the eye (Nat. Commun. 2018, DOI: 10.1038/s41467-018-06981-w). The microneedles have two reservoirs, an inner one made of hyaluronic acid, which dissolves quickly, allowing rapid release of one drug, and an outer one made of cross-linked methacrylated hyaluronic acid, which dissolves more slowly, enabling sustained release of a second drug. When the patch is applied to the eye, the microneedles penetrate the surface. They start dissolving almost immediately and detach from the substrate. In less than a minute, the substrate can be peeled away, leaving the microneedles implanted in the eye. The researchers used the patch to deliver drugs to mice to treat the formation of new blood vessels in response to trauma. They delivered diclofenac, a nonsteroidal anti-inflammatory drug, in the inner layer and an antibody drug targeting abnormal blood vessel formation in the outer layer. The drugs worked together to provide more effective treatment than either drug alone.