New eye phantom for ophthalmic surgery

Abstract

In this work, we designed and realized a new phantom able to mimic the principal mechanical, rheological, and physical cues of the human eye and that can be used as a common benchmark to validate new surgical procedures, innovative vitrectomes, and as a training system for surgeons. This phantom, in particular its synthetic humor vitreous, had the aim of reproducing diffusion properties of the natural eye and can be used as a system to evaluate the pharmacokinetics of drugs and optimization of their dose, limiting animal experiments. The eye phantom was built layer-by-layer starting from the sclera up to the retina, using low cost and easy to process polymers. The validation of the phantom was carried out by mechanical characterization of each layer, by diffusion test with commercial drugs into a purposely developed apparatus, and finally by a team of ophthalmic surgeons. Experiments demonstrated that polycaprolactone, polydimethylsiloxane, and gelatin, properly prepared, are the best materials to mimic the mechanical properties of sclera, choroid, and retina, respectively. A polyvinyl alcohol-gelatin polymeric system is the best for mimicking the viscosity of the human humor vitreous, even if the bevacizumab half-life is lower than in the human eye.

The PK-Eye: A Novel In Vitro Ocular Flow Model for Use in Preclinical Drug Development

“…In addition to in vitro permeation models, other in vitro models have been described for the preclinical development of IVT ophthalmic preparations . For example, the dissolution of poorly soluble drugs and extended‐release tablets were evaluated using a USP4 dissolution apparatus with a flow through of 1.5 mL/min in a chamber of 8–19 mL .…”

Self‐Adhesive Microneedles with Interlocking Features for Sustained Ocular Drug Delivery

“…To prepare a vitreous humor‐mimicking gel, PVA was mixed with a solution containing 2.5% w/v gelatin and water. [ 35 ] The PVA solution to the gelatin water mix had the percentage of 31.5% w/v. The solution was stirred at 70°C.…”

Hydrogel-Forming Microneedle Arrays for Sustained and Controlled Ocular Drug Delivery

“…Then, the base of MNs was wrapped with the parafilm and polyethylene/nylon to create an insulative environment in which only the MNs were in contact with the test solution. The test solution, a vitreous humor mimicking fluid, was prepared following the study by Fogli et al [29]. The partially insulated MNs were attached to the lids of vials and then inserted into wells filled with the vitreous mimicking solution.…”