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

Abstract

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_i 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_i 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_i 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.

• Colloidal dispersions
• in situ gelling systems
• lipid nanoparticles
• ophthalmic
• poloxamers

Acknowledgements

The authors would like to express thanks to Gattefossé (France) for the gift of the excipients.

Declaration of interest

The authors state no conflict of interest.