One-side-coated insert as a unique ophthalmic drug delivery system

Area of Science:

• Ophthalmology
• Pharmaceutics
• Drug Delivery Systems

Background:

• Ophthalmic drug delivery faces challenges with rapid clearance and systemic absorption.
• Developing controlled-release systems is crucial for sustained ocular drug levels.
• One-side-coated inserts offer a potential method to modulate drug release and absorption.

Purpose of the Study:

• To investigate the impact of inserting direction of a novel one-side-coated ophthalmic insert on drug absorption in rabbit eyes.
• To evaluate how the uncoated side's orientation (towards sclera or conjunctiva) influences ocular and systemic drug distribution.
• To assess the release kinetics of a model ophthalmic drug from the one-side-coated insert.

Main Methods:

• Preparation of a unique one-side-coated poly(2-hydroxypropyl methacrylate) insert containing tilisolol.
• Application of inserts in the lower conjunctival cul-de-sac of albino rabbits, with specific orientations (SC vs. CJ).
• Quantification of tilisolol concentrations in tear fluid, plasma, aqueous humor, conjunctiva, and sclera using High-Performance Liquid Chromatography (HPLC).

Main Results:

• The one-side-coated insert exhibited a slower drug release rate compared to an uncoated insert.
• Constant drug concentrations were maintained in tear fluid for 180 minutes with the one-side-coated insert.
• The sclera-facing (SC) insert resulted in higher drug concentrations in the aqueous humor and sclera, but lower concentrations in plasma and conjunctiva compared to the conjunctiva-facing (CJ) insert.

Conclusions:

• The insertion direction of a one-side-coated ophthalmic insert significantly influences ocular and systemic drug absorption.
• This novel insert design provides a method to control drug distribution within the eye and reduce systemic exposure.
• Optimizing the orientation of one-side-coated inserts holds promise for improved ophthalmic therapy.