Cytotoxicity and anti-inflammatory activity of cyclosporine A loaded PLGA nanoparticles for ocular use

Cyclosporine A loaded poly(lactide-co-glycolide) nanoparticles were prepared using the o/w emulsification solvent evaporation method and the effect of four preparation parameters on particle size and zeta potential was investigated. Release properties of the nanoparticles were examined and in vitro experiments were performed in order to evaluate the cytotoxicity and anti-inflammatory activity of the nanoparticles developed. Particle sizes varied between 191 and 303 nm depending on the different preparation parameters and all nanoparticle dispersions were monodisperse. The nanoparticles showed negative zeta potential values varying between -16 and -35 mV and 57 to 70 % of the amount of loaded cyclosporine A was released after 24 h. None of the nanoparticle formulations showed significant cytotoxicity compared to the negative control using human epithelial cells (HaCaT). Cyclosporine A incorporated in the various nanoparticle formulations retained its anti-inflammatory activity as significant suppression of interleukine-2 secretion in concanavalin A stimulated Jurkat T cells was measured. As the overall influence of the freeze-drying process on the characteristics of nanoparticles was limited, trehalose and carnitine should be preferred as cryoprotectants in ocular formulations for treatment of dry eye disease.