Flurbiprofen-loaded acrylate polymer nanosuspensions for ophthalmic application.

Polymeric nanoparticle suspensions were prepared from Eudragit RS100R and RL100R polymer resins and loaded with flurbiprofen (FLU), with the aim at improving the availability of the drug at an intra-ocular level for the prevention of the myosis induced during extracapsular cataract surgery. Nanosuspensions were prepared by a quasi-emulsion solvent diffusion technique using different formulation parameters (drug-to-polymer ratio, initial polymer concentration, agitation speed, etc.). The resulting nanoparticles showed mean sizes around 100 nm and a fixed positive charge (zeta-potential around +40/+60 mV). Stability tests after mid-time storage (4 degrees C or room temperature) or freeze-drying were carried out to optimise a possible final pharmaceutical preparation. In vitro, dissolution tests showed a controlled release profile of FLU from the nanoparticles. In vivo anti-inflammatory efficacy was assessed in the rabbit eye after induction of an ocular trauma (paracentesis). FLU-loaded nanosuspensions did not show toxicity on ocular tissues. Moreover, an inhibition of the miotic response to the surgical trauma comparable to a control eye-drop formulation was obtained, even though an actual lower concentration of free drug in the conjunctival sac was achieved from the nanoparticle system. Drug levels in the aqueous humour were also higher after application of the nanosuspensions.