Development of a hydrophobic polymer composition with improved biocompatibility for making foldable intraocular lenses

• An optical polymer was synthesized using hydrophobic monomers by gamma irradiation.
• Biocompatibility of the resulting polymer was improved by using bio-active material and different functional additives.
• Various process parameters were optimized to result a superior optical material.
• The optical polymer was characterized for optical and mechanical properties as required for intraocular lenses.
• The optical material was evaluated by toxicological tests to establish its biocompatibility.

A hydrophobic composition for foldable intraocular lenses was developed by copolymerizing phenyl ethyl acrylate, phenyl ethyl methacrylate and butanediol diacrylate by gamma irradiation. Aqueous solution of heparin, a biocompatibilizer absorbed in hydroxyethyl methacrylate was added to the monomer mixture before irradiation to impart desired level of hydrophilicity and improved biocompatibility to the hydrophobic composition. Ketorolac tromethamine, an anti-inflammatory agent and L-glutathione, an antioxidant were added to the composition as functional additive for exhibiting improved performance while in use. Concentrations of monomers, biocompatibilizer and functional additives were optimized to develop an advanced material for foldable intraocular lenses. Transmittance, refractive index, Abbe number, hardness, tensile strength, flexibility and foldability were studied on the final composition. Scanning electron microscopic study, differential scanning calorimetric analysis, leachability and viscometry confirmed the permanent incorporation of additives into the polymer. Results of haemocompatibility, tissue implantation and cytotoxicity confirm that the biocompatibility of the base polymer was improved by incorporation of heparin.