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- Surface modification of an intraocular lens material by plasma-assisted grafting with 2-hydroxyethyl methacrylate (HEMA), for controlled release of moxifloxacinPublication . Vieira, Ana Paula; Pimenta, Andreia; Silva, Diana; Gil, Maria; Alves, Patrícia; Coimbra, Patrícia; Mata, Jose; Bozukova, Dimitriya; Correia, Tiago R.; Correia, Ilídio Joaquim Sobreira; Serro, Ana Paula; Guiomar, AntónioEndophthalmitis, an inflammation of the eye due to perioperative infection, may occur after cataract surgery. Intraocular lenses (IOLs) loaded with an antibiotic have been proposed as an alternative to the conventional postoperative endophthalmitis prophylaxis, since the antibiotic is delivered directly to the target site. In this work, an IOL-based antibiotic releasing system was prepared from a copolymer used in the production of IOLs and a fluoroquinolone used in endophthalmitis prophylaxis (moxifloxacin, MFX). Argon plasma-assisted grafting with 2-hydroxyethyl methacrylate (HEMA) in the presence of MFX was the approach selected for surface modification, with MFX loaded both by entrapment in the grafted polyHEMA coating and by soaking. Surface and bulk properties were evaluated before and after surface modification and the MFX release profiles were obtained both in batch mode (sink conditions) and under hydrodynamic conditions, employing a purpose-built microfluidic cell, which simulated the hydrodynamic conditions around the eye lens. The effect of storage on the release profile of the best system was also assessed. The best system released MFX for ca. 15 days above the minimum inhibitory concentration for Staphylococcus aureus and Staphylococcus epidermidis. The released MFX showed antimicrobial activity against these bacteria and was non-cytotoxic against corneal endothelial cells.
- Controlled release of moxifloxacin from intraocular lenses modified by Ar plasma-assisted grafting with AMPS or SBMA: An in vitro studyPublication . Pimenta, Andreia; Vieira, Ana Paula; Colaco, Rogério; Saramago, Benilde; Gil, Maria; Coimbra, Patrícia; Alves, Patrícia; Bozukova, Dimitriya; Correia, Tiago R.; Correia, Ilídio Joaquim Sobreira; Guiomar, António; Serro, A.P.Intraocular lenses (IOLs) present an alternative for extended, local drug delivery in the prevention of post-operative acute endophthalmitis. In the present work, we modified the surface of a hydrophilic acrylic material, used for manufacturing of IOLs, through plasma-assisted grafting copolymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) or [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), with the aim of achieving a controlled and effective drug release. The material was loaded with moxifloxacin (MFX), a commonly used antibiotic for endophthalmitis prevention. The characterization of the modified material showed that relevant properties, like swelling capacity, wettability, refractive index and transmittance, were not affected by the surface modification. Concerning the drug release profiles, the most promising result was obtained when AMPS grafting was done in the presence of MFX. This modification led to a higher amount of drug being released for a longer period of time, which is a requirement for the prevention of endophthalmitis. The material was found to be non-cytotoxic for rabbit corneal endothelial cells. In a second step, prototype IOLs were modified with AMPS and loaded with MFX as previously and, after sterilization and storage (30 days), they were tested under dynamic conditions, in a microfluidic cell with volume and renovation rate similar to the eye aqueous humour. MFX solutions collected in this assay were tested against Staphylococcus aureus and Staphylococcus epidermidis and the released antibiotic proved to be effective against both bacteria until the 12th day of release.