Evaluating the potential of drug eluting contact lenses for treatment of bacterial keratitis using an ex vivo corneal model

Corneal infections are treated by multiple instillations of eye drops each day. This study aims to investigate the effectiveness of ofloxacin-loaded contact lenses as prolonged release devices for the treatment of bacterial keratitis. Two silicone hydrogel contact lenses (SHCLs) Senofilcon A (ACUVUE OASYS (R)) and Narafilcon A (ACUVUE TRUEYE (R)) were modified by incorporation of ofloxacin alone or with vitamin E (VE). The drug uptake and in vitro release kinetics were investigated and the antibacterial efficacy was assessed against Staphylococcus aureus and Pseudomonas aeruginosa in an ex vivo rabbit corneal model. The in vitro studies showed a higher uptake (p <= 0.05) and longer duration of release by Narafilcon A lenses compared to the Senofilcon A lenses. The addition of VE led to a significant increase in duration of release (p < 0.05) for both lenses. The ex vivo studies confirmed the effectiveness of the ofloxacin-loaded lenses in the reduction of bacterial load to clinically insignificant levels and ofloxacin-vitamin E-loaded Narafilcon A lenses in the reduction of bacteria on the corneas to undetectable levels. Antibiotic-loaded lenses are effective in the treatment of ocular infections. Incorporation of vitamin E will sustain this effect and eliminate the need for multiple instillations of eye drops.