Sustained Release Intravitreal Dexamethasone

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Abstract
Sustained intravitreal levels of dexamethasone may be useful in the treatment of proliferative vitreoretinopathy (PVR). The preparation and evaluation of an implantable system for intravitreal sustained release of dexamethasone is described. Pellets of dexamethasone were coated in biocompatible, nonerodible polymers and the release rate tested in vitro. Devices were then implanted in the rabbit vitreous and the in vivo release rate and corresponding steady state vitreous concentration determined. Toxicity was also evaluated by histopathology and electrographic examination. Devices released dexamethasone at approximately 1 ug/hr in vitro and 1.5 ug/hr in vivo. When implanted into the vitreous intravitreal concentrations of approximately 2.5 +/− 1.2 ug/hr were maintained for over 3 months. Devices were well tolerated with no evidence of inflammation or retinal abnormalities.