Efficient Hydrophilic Small Molecule Delivery To Retinal Cell Lines Using Solid Lipid Nanoparticle Containing Gel Core

Abstract

Delivering small hydrophilic drug molecules to the retina is a challenging task in ophthalmology. A solid lipid nanoparticle (SLP) with a composite shell and hydrogel core as delivery system of a hydrophilic cargo to retinal cells has been developed in this work to meet the challenge. The composite shell formed by lipid and hydrophobic polyesters improves polydispersity while the hydrogel core enhances the encapsulation efficiency when compared to conventional SLP. In vitro studies tracking internalization and release of hydrophilic fluorescent dyes in retinal pigment epithelium and photoreceptor cell lines, showed a successful uptake and release of the hydrophilic cargo inside the cells. Validation of SLP encapsulation capability using a neuroprotective cGMP analogue resulted in a SLP size < 250 nm, negative surface charge > -20 mV, and encapsulation efficiency value of 60%. This formulation shows a potential to be applied as ocular drug delivery system and may open new perspectives for developing a treatment for retinal diseases.