Pharmacokinetics and retinal distribution of ranibizumab, a humanized antibody fragment directed against VEGF-A, following intravitreal administration in rabbits

Retina. 2007 Nov-Dec;27(9):1260-6. doi: 10.1097/IAE.0b013e318134eecd.


Purpose: Ranibizumab (Lucentis) is a humanized antigen-binding fragment designed to inhibit all isoforms and active degradation products of vascular endothelial growth factor A (VEGF-A); it is in clinical development for the treatment of neovascular age-related macular degeneration (AMD). This study evaluated its pharmacokinetics (PK) and retinal distribution in rabbits when administered intravitreally (ITV).

Methods: A total of 27 New Zealand white rabbits received a single bilateral ITV injection of ranibizumab 625 muicrog/eye (Group 1, n = 24) or I-labeled ranibizumab 625 microg/eye, 22.5 microCi/eye (Group 2, n = 3). Ranibizumab concentration was determined in the vitreous, aqueous humor, and serum up to 60 days postdose by enzyme-linked immunosorbent assay in Group 1. Group 2 eyes were microautoradiographed on days 1-4.

Results: Ranibizumab has a terminal half-life of 2.9 days in the ocular compartments. Systemic exposure was low, measuring less than 0.01% of vitreous exposure when comparing AUC0-t values. Microautoradiography analysis demonstrated that ranibizumab penetrated all retinal layers, reaching the choriocapillaris on days 1, 2, and 4.

Conclusions: This study demonstrates that following ITV injection, ranibizumab has a vitreous half-life of 2.9 days with minimal systemic exposure. Ranibizumab rapidly penetrates through the retina to reach the choroid, supporting its clinical development for neovascular AMD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiogenesis Inhibitors / pharmacokinetics*
  • Animals
  • Antibodies, Monoclonal / pharmacokinetics*
  • Antibodies, Monoclonal, Humanized
  • Aqueous Humor / metabolism*
  • Autoradiography
  • Enzyme-Linked Immunosorbent Assay
  • Injections
  • Male
  • Rabbits
  • Ranibizumab
  • Retina / metabolism*
  • Tissue Distribution
  • Vascular Endothelial Growth Factor A / antagonists & inhibitors
  • Vitreous Body / metabolism*


  • Angiogenesis Inhibitors
  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Vascular Endothelial Growth Factor A
  • Ranibizumab