Drug eluting contact lenses for cystinosis therapy

Cystinosis is a metabolic disease characterized by accumulation of cysteine crystals in various tissues including cornea. Cystinosis patients begin showing ocular symptoms at the age of 16 months and without appropriate treatment, the entire peripheral stroma and endothelium can be packed with crystals. Eventually complications such as corneal scars and band keratopathy can occur resulting in irreversible damage to the eye.

Cystinosis is treated with an anti-oxidant drug cysteamine (β-mercaptoethylamine), which reacts with cystine to convert it to a more soluble form. The oral dose of cysteamine achieves therapeutic effects in several organs but its concentration in corneal tissue is inadequate to reduce crystal accumulation. Cysteamine eye drops, delivered hourly, are utilized for treating the ocular complications of cystinosis. While the eye-drop based therapy is effective, the high frequency of drop instillation often leads to poor compliance and a significant impact on the quality of life of patients.

The high frequently of eye drop instillation is required because a very large fraction of the drug administered as eye drops is lost to the systemic circulation and because with every blink a large fraction of the drug drains into the nose. A more compliant drug delivery approach can be developed by using a slow releasing device that can preferentially release the drug to the cornea. A contact lens is the ideal choice for the delivery of cysteamine from the contact lenses because of the placement of the contact in proximity to the cornea. Our research suggests that 50% of the drug loaded in the lenses reaches the cornea compared to 1% with eye drops. Our research aims to replace the hourly instillation of eye drops with a daily disposable contact lens that needs to be worn for only a few hours each day.

Award Date
20 June 2014
Award Value
€72,039
Principal Investigator
Ms Anne Marie O'Dowd
Host Institution
Cystinosis Foundation Ireland
Scheme
MRCG-HRB Joint Funding Scheme