The eye patch for ocular drug delivery is equipped with an array of self-implantable micro-drug-reservoirs. (Credit: NTU Singapore)

A contact lens patch with microneedles could provide a painless and efficient alternative to current methods of treating eye diseases such as glaucoma and macular degeneration.

The proof-of-concept patch, successfully tested in mice, is covered with biodegradable microneedles that deliver drugs into the eye in a controlled release. After pressing it onto the eye surface briefly and gently – much like putting on contact lenses – the drug-containing microneedles detach by themselves and stay in the cornea, releasing the drug over time as they dissolve.

When tested on mice with corneal vascularization, a single application of the patch was 90 percent more effective in alleviating the condition than applying a single eye drop with 10 times more drug content.

To tackle these problems, the team developed a 2 x 2mm patch with nine microneedles that can be loaded with drugs for lab tests. Each needle, thinner than a strand of hair, is shaped like a pyramid for optimal tissue penetration. The needle is made of hyaluronic acid, a substance found in the eye and is used often in eye drops. A modified version of the hyaluronic acid is added to form a second layer of the needle to slow down the rate at which the needle degrades, ensuring a slower release of the drug.

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