Suprachoroidal Drug Delivery to the Back of the Eye Using Hollow Microneedles
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In this work, we tested the hypothesis that microneedles provide a minimally invasive method to inject particles into the suprachoroidal space for drug delivery to the back of the eye.
A single, hollow microneedle was inserted into the sclera, and infused nanoparticle and microparticle suspensions into the suprachoroidal space. Experiments were performed on whole rabbit, pig, and human eyes ex vivo. Particle delivery was imaged using brightfield and fluorescence microscopy as well as microcomputed tomography.
Microneedles were shown to deliver sulforhodamine B as well as nanoparticle and microparticle suspensions into the suprachoroidal space of rabbit, pig, and human eyes. Volumes up to 35 μL were administered consistently. Optimization of the delivery device parameters showed that microneedle length, pressure, and particle size played an important role in determining successful delivery into the suprachoroidal space. Needle lengths of 800–1,000 μm and applied pressures of 250–300 kPa provided most reliable delivery.
Microneedles were shown for the first time to deliver nanoparticle and microparticle suspensions into the suprachoroidal space of rabbit, pig and human eyes. This shows that microneedles may provide a minimally invasive method for controlled drug delivery to the back of the eye.
KEY WORDSeye suprachoroidal space hollow microneedle microparticle nanoparticle ocular drug delivery
We would like to thank Dr. Harvinder Gill and Dr. John Nickerson for helpful discussions and Donna Bondy for administrative support. This work was carried out at the Emory Eye Center and at the Center for Drug Design, Development and Delivery and the Institute for Bioengineering and Bioscience at Georgia Tech. This work was supported in part by the National Eye Institute (R24-EY-017045). M.R.P. serves as a consultant and is an inventor on patents licensed to companies developing microneedle-based products. This possible conflict of interest has been disclosed and is being managed by Georgia Tech and Emory University.