The active form of fingolimod (FTY720; FT) is a sphingosine-1-phosphate receptor agonist with potential ocular applications. The goal of the present study was to develop an FT-loaded nanoemulsion (NE; FT-NE) formulation for the efficient and prolonged delivery of FT to the posterior segment of the eye through the topical route. FT-NE formulations were prepared with homogenization followed by probe sonication method. The lead FT-NE formulation (0.15% and 0.3% w/v loading), comprising soybean oil as lipid and Tween® 80 and Poloxamer 188 as surfactants, was further evaluated for in vitro release, surface morphology, filtration sterilization, and stability at refrigerated temperature. The formulation, at both dose levels, showed desirable physicochemical characteristics, a nearly spherical shape with homogenous nanometric size distribution, and was stable for 180 days (last time point checked) at refrigerated temperature post-filtration through polyethersulfone (0.22 µm) membrane. In vitro release studies showed prolonged release, compared with the control FT solution (FT-S), over 24 h. The results from these studies demonstrate that the FT-NE formulation can serve as a viable platform for the ocular delivery of FT through the topical route.

Imbalance in the oxidative status in neurons, along with mitochondrial damage, are common characteristics in some neurodegenerative diseases. The maintenance in energy production is crucial to face and recover from the oxidative damage and the coexistence of different sources of energy production, such as mitochondrial and glycolytic ATP, allows faster adaptative mechanisms to situations of high energy demand and may help in the maintenance of neuronal function in stress situations. Fingolimod phosphate is a drug with neuroprotective and antioxidant actions, used in the treatment of Multiple Sclerosis. This work has been performed in a model of oxidative damage on neuronal cell cultures exposed to menadione, in presence or absence of fingolimod phosphate. We have studied the mitochondrial function and several pathways related with glucose metabolism, including oxidative, glycolytic and pentose phosphate in neuronal cells cultures. Our results showed a beneficial effect on neuronal survival probably based in the recovery of all, oxidative balance, glycolysis and pentose phosphate, promoted by fingolimod phosphate. These effects are mediated, at least in part by the interaction with its specific receptor. These actions would make this drug a potential tool to the treatment of neurodegenerative processes, either to slow progression or alleviate symptoms.