Chitosan-associated SLN: in vitro and ex vivo characterization of cyclosporine A loaded ophthalmic systems

The aim of this study was to develop cyclosporine A (CsA) loaded solid lipid nanoparticles (SLN) associated with chitosan (CS), to improve interaction and internalization in corneal cells. The SLN were prepared using high shear homogenization and ultrasound methods with CS in the aqueous phase. The lipid phase was based on Compritol or Precirol. The SLN were characterized for particle size, polydispersity index, morphology, zeta potential and encapsulation efficiency. The systems were freeze-dried to increase physical stability and trehalose was used as a cryo/lyo-protector to stabilize the SLN. The penetration and permeation properties of the SLN were assessed in vitro (cell culture) and ex vivo (excised pig cornea). The cell uptake of SLN was studied by means of confocal laser scanning microscopy. CS-associated SLN based on Compritol were biocompatible and enhanced the permeation/penetration of CsA along with a possible mechanism of internalization/uptake of the nanoparticles both in vitro and ex vivo.