Development and characterization of Cyclosporine A loaded nanoparticles for ocular drug delivery: Cellular toxicity, uptake, and kinetic studies.

Dry eye syndrome is a common disorder of the tear film caused by decreased tear production or increased evaporation. The objective of this study was to evaluate the potential effectiveness of Cyclosporine A (CsA) nanoparticles (NPs) for the treatment of inflammation of the eye surface. Topical CsA is currently the only and safe pharmacologic treatment of severe dry eye symptoms. The NPs were prepared using either poly-lactide-co-glycolide (PLGA) or a mixture of PLGA with Eudragit®RL or were coated with Carbopol®. The mean size of CsA loaded NPs was within the range from 148 to 219nm, except for the Carbopol® coated NPs (393nm). The drug entrapment efficiency was very high (from 83 to 95%) and production yield was found between 75 and 92% in all preparations. The zeta potential of the Eudragit® RL containing NPs was positive (19-25mV). The NPs formulations exhibited a biphasic drug release with initial burst followed by a very slow drug release and total cumulative release within 24h ranged from 75 to 90%. Kinetically, the release profiles of CsA from NPs appeared to fit best with the Weibull model. The viability of L929 cells was decreased by increasing the concentration of the various NPs examined as well as the incubation time. The amount of NPs uptake was related to the polymer type used. The highest degree of cellular uptake (52.2%), tear film concentration of the drug (366.3ng/g) and AUC(0→24) (972.6ngh/g) value were obtained from PLGA: Eudragit® RL (75:25)-CsA NPs formulations. The change of surface characteristics of NPs represents a useful approach for improvement of ocular retention and drug availability.