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Cidofovir transport in the pigmented rabbit conjunctiva
1Department of Pharmaceutical Sciences, University of Southern California, Los Angeles 90033, USA.
Current Eye Research
|July 1, 1997
Summary
Cidofovir transport across the rabbit conjunctiva likely occurs via paracellular passive diffusion. Formulation adjustments can potentially enhance cidofovir absorption through the conjunctival route.
Area of Science:
- Ocular pharmacology
- Drug delivery systems
- Biophysical transport mechanisms
Background:
- Cidofovir is an antiviral medication.
- Understanding drug transport across the conjunctiva is crucial for ocular drug delivery.
- The pigmented rabbit conjunctiva serves as a model for studying ocular drug absorption.
Purpose of the Study:
- To characterize the transport of cidofovir across the pigmented rabbit conjunctiva.
- To investigate the influence of formulation on cidofovir transport.
Main Methods:
- Excised pigmented rabbit conjunctiva mounted in a Ussing chamber.
- 3H-cidofovir applied to the donor compartment, radioactivity measured in the receiver fluid over 180 minutes.
- Assessed effects of hypotonicity, EDTA, and benzalkonium chloride on cidofovir transport and transconjunctival electrical resistance.
Main Results:
- Cidofovir flux increased proportionally with concentration (0.01-1 mM).
- Transport was similar in both directions and at different temperatures (4°C vs. 37°C).
- Hypotonicity, EDTA, and benzalkonium chloride significantly increased cidofovir permeability and reduced electrical resistance, suggesting paracellular diffusion.
Conclusions:
- Cidofovir transport in the rabbit conjunctiva appears to be mediated by paracellular passive diffusion.
- Formulation modifications hold potential for improving cidofovir absorption via the conjunctival route.
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