Abstract
Purpose To evaluate the ocular pharmacokinetic properties of subretinal conbercept injection in vitrectomized rabbit eyes and to compare them with those by intravitreal injection. Methods The following groups of New Zealand white rabbits received conbercept injections (0.5 mg/0.05 ml): a subretinal group (subretinal injection in vitrectomized eyes), an intravitreal group (intravitreal injection in vitrectomized eyes), and a control group (intravitreal injection in nonvitrectomized eyes). Drug concentrations in the aqueous humor (AH), the vitreous humor (VH), and the retina were measured by the enzyme-linked immunosorbent assay (ELISA), and pharmacokinetic parameters were calculated. Ophthalmic B-ultrasonography, electroretinogram (ERG), and hematoxylin and eosin (H&E) staining were performed to evaluate the safety of subretinal injection. Results On the 28th day after injection, the drug level in the subretinal group was significantly higher than that in the intravitreal group in the AH (0.90 ± 0.25 μg/ml and 0.11 ± 0.07 μg/ml and 0.11 ± 0.07 P < 0.001, respectively) and the VH (5.00 ± 3.86 μg/ml and 0.11 ± 0.07 μg/ml and 0.11 ± 0.07 P < 0.001, respectively) and the VH (5.00 ± 3.86 P < 0.001, respectively) and the VH (5.00 ± 3.86 P < 0.001, respectively) and the VH (5.00 ± 3.86 Conclusions Our study indicates that applying conbercept by subretinal injection can reduce the drug clearance rate and sustain a long maintenance period in ocular tissue, which suggests that subretinal conbercept injection may be a potentially valuable treatment option.
Highlights
Submacular hemorrhage (SMH) is a vision-threatening complication of neovascular age-related macular degeneration (AMD) and usually requires surgical management
According to subretinal or intravitreal application of conbercept, the rabbits were randomly assigned to 3 groups: a subretinal group, an intravitreal group, and a control group. e concentrations of conbercept in the aqueous humor (AH) and the vitreous humor (VH) following administration of a single 0.5 mg dose to the left eyes in the groups were tested. e drug levels in the AH and the VH were highest at the 1st time point (1 day) in the three groups, and the drug level in the subretinal group manifested a slower decline than that in the other two groups after the 3rd (7 days) time point (Figures 1(a) and 1(b))
Conbercept is composed of human Vascular endothelial growth factor (VEGF) receptor 1, VEGF receptor 2, and the Fc fragment of human IgG1 [8]. is large fusion protein is unlikely to cause systemic complications because its permeability through blood-ocular barriers is hindered by its 143 kDa molecular size [8, 9]. erefore, subretinal injection of this large protein is relatively safe
Summary
Submacular hemorrhage (SMH) is a vision-threatening complication of neovascular age-related macular degeneration (AMD) and usually requires surgical management. Vascular endothelial growth factor (VEGF) is crucial in angiogenesis because it is highly selective for endothelial cells and reaches its target by diffusion [2, 3], and the application of antiVEGF agents during surgery could contribute to the prevention of CNV progression or recurrence [4, 5]. The current practice of intravitreal injection of anti-VEGF agents has produced an effective therapeutic response, research has shown that subretinal application can ensure. To reduce the damage to the retina cells caused by bleeding, vitrectomy with subretinal anti-VEGF injection is usually required
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