title: Serum levels of intravitreal bevacizumab after vitrectomy, lensectomy and non-surgical controls.
abstract: OBJECTIVE
  To determine serum level differences of intravitreally-placed bevacizumab after vitrectomy and lensectomy-vitrectomy and to compare these with non-operated eyes in a rabbit model.
  
  
  METHODS
  Five Dutch-belted rabbits underwent pars plana vitrectomy (PPV), five rabbits underwent pars plana lensectomy (PPL) and five rabbits served as non-surgical controls. Twelve days following the surgical procedures, each operated eye underwent an intravitreal injection consisting of 1.25 mg/0.05 mL bevacizumab. Serum levels from each rabbit were drawn on days 2, 4, 7, 10, 14, 21, 28 and 35 and were measured with ELISA immunoassay.
  
  
  RESULTS
  The average peak serum concentration (Cmax) was highest for the PPL group (11.33 μg ± 3.48 mL), and was similar between the PPV (5.35 μg ± 2.69 mL) and non-surgical control groups (5.35 μg ± 0.69 mL). The average time to maximal plasma concentration (Tmax) in days was earliest for the PPL group (2.8 ± 0.47), followed by the PPV (5.6 ± 0.84) and non-surgical control groups (6.4 ± 0.71). The PPL group had higher serum levels than the other two groups until day 7 that was significant only at day 2 (p < 0.0001). After day 4, there were no significant differences or trends between any of the three groups. The half-life (T1/2) was fastest for the PPL group (1.41 ± 0.21 d) followed by the PPV (2.80 ± 3.35 d) and non-surgical control groups (6.69 ± 10.4 d).
  
  
  CONCLUSIONS
  Serum bevacizumab levels were initially elevated following lensectomy and vitrectomy compared to non-surgical eyes following intravitreal injection. The half-life of bevacizumab was prolonged in non-surgical eyes presumably due to a slower release from the vitreous cavity.
authors.affiliation: Department of Ophthalmology & Visual Science, College of Medicine, The University of Arizona, Tucson, AZ, USA . john.christoforidis@osumc.edu
authors.forename: John B
authors.initials: JB
authors.lastname: Christoforidis
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Xie
authors.forename: Angela
authors.initials: A
authors.lastname: Jiang
authors.forename: Jillian
authors.initials: J
authors.lastname: Wang
authors.forename: Cedric
authors.initials: C
authors.lastname: Pratt
authors.forename: Anne
authors.initials: A
authors.lastname: Gemensky-Metzler
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Abdel-Rasoul
authors.forename: Sashwati
authors.initials: S
authors.lastname: Roy
authors.forename: Zhongfa
authors.initials: Z
authors.lastname: Liu
mesh_terms: D020533:Angiogenesis Inhibitors / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000068258:Bevacizumab; D004797:Enzyme-Linked Immunosorbent Assay; D006207:Half-Life; D058449:Intravitreal Injections; D007908:Lens, Crystalline / Q000601:surgery*; D008297:Male; D011817:Rabbits; D014821:Vitrectomy
chemical_list: D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab
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