Injection Site and Pharmacokinetics After Intravitreal Injection of Immunoglobulin G

Abstract Purpose: The aim of this study was to investigate whether the pharmacokinetics differ after immunoglobulin G (IgG) intravitreal injections are done in the different sites of the vitreous cavity of rabbit eyes. Methods: To examine the pharmacokinetics in the vitreous and the retina/choroid, fluorescein isothiocyanate-labeled IgG (5 μg/50 μL) was injected from the superior pars plana into the vitreous cavity of rabbit eyes. An original intravitreal injection guide was used to fix the tip of the injection needle, with the tip fixed in either the superior-anterior vitreous (superior group) or in the posterior vitreous (posterior group). At 1 h, 1, 4, and 7 days after injection, the eyes were enucleated and frozen. The vitreous was cut into superior, inferior, and posterior vitreous sections, whereas the retina/choroid was cut into superior, inferior, and posterior retina/choroid sections. The IgG concentrations in the vitreous and the retina/choroid sections were then determined. Results: In the post...