Abstract
Purpose: :
Intravitreal injection of angiogenesis inhibitors has become commonplace in the treatment of retinal diseases, such as age related macular degeneration and proliferative diabetic retinopathy. Unfortunately, this route of delivery requires repeated injections, increasing the risk of infection and retinal injury. The purpose of this study is to determine the length of time nanoparticles can be retained in the vitreous chamber after pars plana injection, and to explore the possible use of these drug carriers for long term treatment of diseases of the retina.
Methods: :
This study was conducted on 9 rabbit eyes and included 3 groups. The control group received a 100 µL intravitreal injection of saline, the Uncoated group received 100 µL of intravitreal 200 nm uncoated latex particle solution, and the Coated group received 100 µL of intravitreal 200 nm latex particles coated with a polymer to prevent aggregation. The baseline fluorescence and intraocular pressures (IOP) were assessed prior to injection through the pars plana. The particles were fluorescence tagged and assessment of retention was made by analysis of in vivo fluorescence imaging. Images and IOP measurements were obtained at 0 min, 1 hr, daily for 1 week and every 5 days for one month. The fluorescence images from each time point were compared to those obtained immediately after the intravitreal injection to determine the relative retention rates for each eye.
Results: :
There was no significant difference between the clearance profiles of the coated and uncoated particles; and there was no significant decline in the particles retained in the vitreous chambers in 30 days. (P<0.05) There was no detectable fluorescence signal in the control group. There were no changes in IOP in any group.
Conclusions: :
Nanoparticles, which can offer sustained and predictable release of medications, may be an effective system for long-term intravitreal drug delivery and the treatment of various retinal diseases.
Keywords: retina • vitreous • age-related macular degeneration