Aqueous Humor Concentration of Bevacizumab After Subconjunctival Injection in Rabbit

Purpose: To investigate whether bevacizumab may be delivered into the anterior chamber after subconjunctival administration and its pharmacokinetics in aqueous humor. Methods: The right eye of 33 rabbits received subconjunctival injection of 2.5 mg of subconjunctival bevacizumab. Three rabbits were sacrificed at each of the following time points: 0.5, 1, 2, 4, 8, 12, 24, 48, 72, 120, 168 h after the injection. Bevacizumab concentrations were measured in aqueous fluid of injected and uninjected eyes and serum using enzyme-linked immunosorbent assay. Results: Bevacizumab was first detected in the aqueous humor of the injected eye at 12 h after the subconjunctival injection. A peak concentration of 70.59 +/- 26.01 ng/mL was achieved at 36 h. Bevacizumab was also detected in the serum and aqueous humor of the uninjected contralateral eye. The concentration in the aqueous humor of the injected eye was lower than in the serum and higher than in the aqueous humor of the uninjected contralateral eye at all time points. Elimination of bevacizumab from the serum and aqueous humor of injected and uninjected eye paralleled with half-life of 57.78 +/- 13.75 h, 27.64 +/- 1.95 h and 28.05 +/- 2.55 h, respectively. Conclusions: We demonstrated that bevacizumab can be delivered into anterior chamber by single subconjunctival injection. Further study is needed to assess whether subconjunctival bevacizumab is clinically useful in patients with neovascular glaucoma.