0
Review Article

Diffusive Transport in the Vitreous Humor: Experimental and Analytical Studies

[+] Author and Article Information
Anita Penkova

Department of Aerospace & Mechanical Engineering, University of Southern California, Los Angeles, CA 90089-1453; Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA 90027
penkova@usc.edu

Rex Moats

Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089-1111; Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA 90027
RMoats@chla.usc.edu

Mark S. Humayun

Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089-1111; Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine, Los Angeles, CA 90033-4682
humayun@usc.edu

Scott Fraser

Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089-1111; Departments of Pediatrics, Ophthalmology, Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033-4682; Departments of Molecular and Computational Biology, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, CA 90089-0371
sfraser@provost.usc.edu

S.S. Sadhal

Department of Aerospace & Mechanical Engineering, University of Southern California, Los Angeles, CA 90089-1453; Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA 90027; Department of Ophthalmology, USC Roski Eye Institute, Keck School of Medicine, Los Angeles, CA 90033-4682
sadhal@usc.edu

1Corresponding author.

ASME doi:10.1115/1.4042297 History: Received September 18, 2018; Revised December 11, 2018

Abstract

In relation to intravitreal drug delivery, predictive mathematical models for drug transport are being developed, and to effectively implement these for retinal delivery, the information on biophysical properties of various ocular tissues is fundamentally important. It is therefore necessary to accurately measure the diffusion coefficient of drugs and drug surrogates in the vitreous humor. In this review, we present the studies conducted by various researchers on such measurements over the last several decades. These include imaging techniques (fluorescence and MRI) that make use of introducing a contrast agent or a labeled drug into the vitreous and tracking its diffusive movement through at various time points. A predictive model for the same initial conditions when matched with the experimental measurements provides the diffusion coefficient, leading to results for various molecules ranging in size from approximately 100 Da to 150 kDa. For real drugs, the effectiveness of this system depends on the successful labeling of the drugs with suitable contrast agents such as fluorescein and gadolinium or manganese so that fluorescence or MR imagining could be conducted. Besides this technique, some work has been carried out using the diffusion apparatus for measuring permeation of a drug across an excised vitreous body from a donor chamber to the receptor by sampling assays from the chambers at various time intervals. This has the advantage of not requiring labeling but is otherwise more disruptive to the vitreous. Some success with nanoparticles has been achieved using dynamic light scattering, and presently, radioactive labeling is being explored.

Copyright (c) 2018 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In