Contact lenses for antifungal ocular drug delivery: a review

Fungal keratitis, a potentially blinding disease, has been difficult to treat due to the limited number of approved antifungal drugs and the taxing dosing regimen. Thus, the development of a contact lens (CL) as an antifungal drug delivery platform has the potential to improve the treatment of fungal keratitis. A CL can serve as a drug reservoir to continuously release drugs to the cornea, while limiting drug loss through tears, blinking, drainage and non-specific absorption.

This review will provide a summary of currently available methods for delivering antifungal drugs from commercial and model CLs, including vitamin E coating, impregnated drug films, cyclodextrin-functionalized hydrogels, polyelectrolyte hydrogels and molecular imprinting. This review will also highlight some of the main factors that influence antifungal drug delivery with CLs.

Several novel CL materials have been developed, capable of extended drug release profiles with a wide range of antifungal drugs lasting from 8 h to as long as 21 days. However, there are factors, such as first-order release kinetics, effectiveness of continuous drug release, microbial resistance, ocular toxicity and potential complications from inserting a CL in an infected eye, that still need to be addressed before commercial applications can be realized.