Surface modification of intraocular lenses towards controlled drug delivery

Purpose Ocular drug delivery systems replacing or complementing the usual therapeutics after cataract surgery have been the focus of several studies. A possible solution could be implanting intra-ocular lenses (IOLs) also acting as drug carriers. The main challenge is to obtain IOLs that besides providing the best refractive outcome release the drug at a suitable rate. The purpose of our research was to design an effective strategy to incorporate the drug and study the release profile. Methods IOL surface was modified with PHEMA [poly(2-hydroxyethyl methacrylate)] by treatment with argon plasma and subsequent immersion in a HEMA solution with moxifloxacin (MFX; Vigamox®), followed by a final immersion in an MFX solution. Drug release profiles were obtained in vitro under hydrodynamic conditions, which simulate those found in the eye for the aqueous humor. A microfluidic cell with a volume of 250 μL was designed and used with a continuous flow of saline solution, at 37°C, with a renovation rate similar to the physiological one. Results Results showed that MFX was released with concentrations above the minimum inhibitory concentrations for S. aureus, S. epidermidis and S. pneumoniae for 11 days. Conclusions In the conditions described, IOLs surface modification with PHEMA has allowed an extended drug release effective to prevent post cataract surgery endophthalmitis.