March 2012
Volume 53, Issue 14
Free
ARVO Annual Meeting Abstract  |   March 2012
Translational diffusion of ranibizumab and bevacizumab as measured by Fluorescence Recovery after Photobleaching (FRAP)
Author Affiliations & Notes
  • Nishanthan Srikantha
    Ophthalmology,
    Kings College London, London, United Kingdom
  • Klaus Suhling
    Physics,
    Kings College London, London, United Kingdom
  • Tim Jackson
    Ophthalmology,
    Kings College London, London, United Kingdom
  • Footnotes
    Commercial Relationships  Nishanthan Srikantha, None; Klaus Suhling, None; Tim Jackson, None
  • Footnotes
    Support  Fight for Sight
Investigative Ophthalmology & Visual Science March 2012, Vol.53, 6488. doi:
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    • Get Citation

      Nishanthan Srikantha, Klaus Suhling, Tim Jackson; Translational diffusion of ranibizumab and bevacizumab as measured by Fluorescence Recovery after Photobleaching (FRAP). Invest. Ophthalmol. Vis. Sci. 2012;53(14):6488.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract
 
Purpose:
 

Some clinical studies indicate that the 149,000 Dalton bevacizumab and 48,000 Dalton ranibizumab have similar therapeutic effects. It would be expected that ranibizumab is more effective as its lower molecular weight should facilitate diffusion through the vitreous body to the retina. This study aimed to determine the diffusion coefficient of both drugs.

 
Methods:
 

The translational diffusion of fluorescently labeled ranibizumab and bevacizumab were determined using fluorescence recovery after photobleaching (FRAP). The translational diffusion coefficient was used to calculate an approximate size for both drugs, and to predict the speed of diffusion through vitreous.

 
Results:
 

Studies show that porcine vitreous is 6.29 ± 2.3centipoise (cp). At this viscosity the diffusion coefficient for ranibizumab and bevacizumab is 2.08x10-13and 1.50x10-13 repectively. Based on translational diffusion coefficients, ranibizumab has a molecular radius of 6.43nm and bevacizumab 9.00nm. These results predict that ranibizumab would diffuse through vitreous 1.39 times faster than bevacizumab.

 
Conclusions:
 

Ranibizumab is able to reach its target tissue faster than bevacizumab. The effects on drug elimination is harder to predict, but the results are consistent with animal studies showing that ranibizumab has a shorter half-life than bevacizumab. Further studies are needed.  

 

 
Keywords: age-related macular degeneration • vitreous • retina 
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