A Controlled Release System for Long-Acting Intravitreal Delivery of Small Molecules

Area of Science:

• Ophthalmology
• Drug Delivery
• Biotechnology

Background:

• Short intravitreal half-lives of small molecule drugs necessitate frequent injections, posing challenges for chronic eye disease management.
• Developing sustained-release intravitreal drug delivery systems is crucial for improving patient compliance and therapeutic outcomes.

Purpose of the Study:

• To engineer a long-acting intravitreal delivery system for small molecule drugs.
• To increase the therapeutic efficacy and reduce injection frequency for ocular treatments.

Main Methods:

• Adapted controlled-release technology using macromolecular carriers for intravitreal administration.
• Covalently attached a complement factor D inhibitor to a 4-arm polyethylene glycol (PEG) carrier via a self-cleaving linker.

Main Results:

• In rabbits, the PEG-drug conjugate demonstrated an intravitreal half-life of 7 days, with the released drug having a half-life of 3.6 days.
• Simulations in human vitreous predicted a conjugate half-life of approximately 2 weeks and a released drug half-life of 5 days.
• The linker's cleavage half-life was optimized to approximately 1 week for sustained drug release.

Conclusions:

• A 2-week linker cleavage half-life could yield a 7-day drug half-life in humans, comparable to existing macromolecular therapies.
• This technology may allow monthly intravitreal injections of potent small molecule drugs for chronic ocular conditions.