Preparation, characterization and biocompatibility studies of thermoresponsive eyedrops based on the combination of nanostructured lipid carriers (NLC) and the polymer Pluronic F-127 for controlled delivery of ibuprofen.

CONTEXT

Nanostructured lipid carrier (NLC) dispersions present low viscosity and poor mucoadhesive properties, which reduce the pre-corneal residence time and consequently, the bioavailability of ocular drugs.

OBJECTIVE

The aim of this study was to prepare thermoresponsive eyedrops based on the combination of lipid nanoparticles and a thermoresponsive polymer with mucomimetic properties (Pluronic® F-127).

MATERIALS AND METHODS

NLC dispersions were prepared based on the melt-emulsification and ultrasonication technique. Physicochemical and morphological characteristics of the colloidal dispersions were evaluated. The formulation was also investigated for potential cytotoxicity in Y-79 human retinoblastoma cells and the in vitro drug release profile of the ibuprofen was determined.

RESULTS

NLC showed a Z-average below 200 nm, a highly positive zeta potential and an efficiency of encapsulation (EE) of ∼90%. The gelification of the NLC dispersion with 15% (w/w) Pluronic® F-127 did not cause significant changes to the physicochemical properties. The potential NLC-induced cytotoxicity was evaluated by the Alamar Blue reduction assay in Y-79 cells, and no relevant cytotoxicity was observed after exposure to 0-100 µg/mL NLC for up to 72 hours. The optimized formulations showed a sustained release of ibuprofen over several hours.

DISCUSSION AND CONCLUSION

The strategy proposed in this work can be successfully used to increase the bioavailability and the therapeutic efficacy of conventional eyedrops.