Enhanced ocular anti-inflammatory activity of ibuprofen carried by an Eudragit RS100 nanoparticle suspension

PURPOSE: To investigate the ocular pharmacodynamic profile of a polymer nanoparticle system loaded with sodium ibuprofen (IBU-RS) in comparison to an aqueous solution of ibuprofen lysinate (IBL) in the rabbit eye both being applied topically. METHODS: Ocular inflammation was elicited by topical application of sodium arachidonate. Inflammation was quantified according to a modified Draize test. The protein level and the number of polymorphonuclear leukocytes in the aqueous humor were assessed after 2 h from arachidonate instillation. The ibuprofen concentration in the aqueous humor was evaluated by HPLC assay. The physico-chemical properties of nanoparticles were also evaluated. RESULTS: The IBU-RS nanosuspension formulation significantly reduced the primary signs of ocular inflammation as well as significantly reducing the protein level and the number of polymorphonuclear leukocytes in the aqueous humor compared with the IBL formulation. Furthermore, the aqueous humor drug concentration from the group treated with IBU-RS was significantly higher compared to the IBL-treated group. The IBU-RS nanosuspensions showed very interesting size and surface charge values, adequate for ophthalmic administration. CONCLUSIONS: The pharmacological profile of the topical IBU-RS nanosuspension formulation described in this study indicates that the dispersion of the drug within RS polymer nanoparticles increased its ocular bioavailability and ultimately its pharmacological activity.