title: Intraocular pharmacokinetics of ranibizumab following a single intravitreal injection in humans.
abstract: OBJECTIVE
  To investigate intraocular concentrations and pharmacokinetics of ranibizumab after a single intravitreal injection in humans.
  
  
  METHODS
  Prospective, noncomparative, interventional case series.
  
  
  METHODS
  We included 18 nonvitrectomized eyes of 18 patients (age range, 61-85 years) that were diagnosed with both clinically significant cataract and macular edema secondary to either exudative age-related macular degeneration, diabetic maculopathy, or retinal vein occlusion. Each eye received a single intravitreal injection of 0.5 mg ranibizumab. An aqueous humor sample was obtained during cataract surgery between 1 and 37 days after injection. Concentrations of unbound ranibizumab in these samples were quantified by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  Ranibizumab concentration in aqueous humor peaked the first day after injection (range, 36.9-66.1 μg/mL) and subsequently declined in a mono-exponential fashion. Nonlinear regression analysis determined an initial peak concentration (c(max)) of 56.1 μg/mL and an elimination half-life (t(1/2)) of 7.19 days with a coefficient of determination (R(2)) of 0.90. Correction of ranibizumab concentrations for ocular volume as calculated from axial length measurements did not alter regression analysis results significantly (t(1/2), 7.15 days; R(2), 0.89).
  
  
  CONCLUSIONS
  In human nonvitrectomized eyes, the aqueous half-life of 0.5 mg intravitreally injected ranibizumab is 7.19 days, slightly shorter than the half-life of 9.82 days previously determined for bevacizumab by comparable methods.
authors: University of Bonn, Department of Ophthalmology, Germany. krohne@uni-bonn.de
authors: Tim U
authors: TU
authors: Krohne
authors: Zengping
authors: Z
authors: Liu
authors: Frank G
authors: FG
authors: Holz
authors: Carsten H
authors: CH
authors: Meyer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D020533:Angiogenesis Inhibitors / Q000493:pharmacokinetics*; D061067:Antibodies, Monoclonal, Humanized / Q000493:pharmacokinetics*; D001082:Aqueous Humor / Q000378:metabolism*; D058452:Axial Length, Eye; D001682:Biological Availability; D001699:Biometry; D002386:Cataract / Q000209:etiology / Q000378:metabolism; D002387:Cataract Extraction; D003930:Diabetic Retinopathy / Q000150:complications / Q000188:drug therapy / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006207:Half-Life; D006801:Humans; D058449:Intravitreal Injections; D008268:Macular Degeneration / Q000150:complications / Q000188:drug therapy / Q000378:metabolism; D008269:Macular Edema / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D000069579:Ranibizumab; D012170:Retinal Vein Occlusion / Q000150:complications / Q000188:drug therapy / Q000378:metabolism
chemical_list: D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; D000069579:Ranibizumab