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The effect of hydration and matrix composition on solute diffusion in rabbit sclera
O A Boubriak1, J P Urban, S Akhtar
1Laboratory of Ophthalmology, University of Oxford, UK.
Experimental Eye Research
|October 21, 2000
Summary
Drug delivery via the sclera is a promising alternative route. Scleral hydration and solute molecular weight significantly impact drug transport, while glycosaminoglycan removal has minimal effect.
Area of Science:
- Ophthalmology
- Biomaterials Science
- Drug Delivery Systems
Background:
- The conjunctiva-cornea pathway is the primary route for ocular drug delivery.
- Drug delivery directly into the vitreous humor offers an alternative to systemic administration.
- The sclera's role in transscleral drug delivery requires further investigation.
Purpose of the Study:
- To investigate the influence of scleral composition and hydration on solute transport.
- To evaluate the rabbit sclera as a model for transscleral drug delivery.
- To determine the effects of specific tissue treatments on solute permeability.
Main Methods:
- Excised rabbit sclera was treated with chondroitinase ABC or glutaraldehyde.
- Ultrastructural analysis assessed tissue changes.
- Diffusion and partition coefficients were measured for various molecular weight solutes.
Main Results:
- Solute transport (diffusion and partition coefficients) decreased with increasing molecular weight.
- Increased scleral hydration significantly enhanced solute transport.
- Glutaraldehyde crosslinking reduced partition coefficients for larger solutes (>3 kDa).
- Chondroitinase ABC treatment showed minimal impact on solute transport.
Conclusions:
- Scleral hydration and solute molecular weight are critical factors in transscleral drug delivery.
- Scleral crosslinking can modulate drug permeability.
- The sclera's glycosaminoglycan content plays a minor role in solute transport.