Abstract
Purpose :
Quercetin (QUE) and resveratrol (RSV), natural occurring polyphenols, have been proven to be a potential new line of treatments for the ocular surface diseases related to oxidative stress. To use these molecules as a topical treatment, a formulation strategy is required due to their low bioavailability.Our aim was to encapsulate QUE and RSV into Elastin-like recombinamer nanoparticles (NPs) and test their biocompatibility and antioxidant activity in vitro on a Human Corneal Epithelial (HCE) cell line and assess their penetration of corneal tissues ex vivo on excised porcine eyes.
Methods :
The biocompatibility of the NPs containing QUE, RSV or both with the HCE cells was assessed by the XTT cell viability assay after a 24-hour exposure.To induce oxidative stress, HCE cells were subjected to UV-B light. The antioxidant activity of NPs was evaluated using H2DCFDA, a fluorescent indicator of reactive oxygen species (ROS). For QUE and QUE/RSV containing NPs the concentration range employed was 5-50 μM, while for RSV NPs this was 25-300 μM.To ex vivo evaluate the permeation through porcine corneal tissues, NPs were loaded with Nile Red, a fluorescent dye used as hydrophobic model drug.All experiments were performed in triplicate (n=3). The statistical analysis of data was performed via ANOVA followed by Games-Howell or Tukey’s post-hoc tests.
Results :
None of the formulations reduced the viability of HCE cells. At the highest concentration of QUE in the NPs, 79 % (p<0.01) of total intracellular ROS was scavenged, while the NPs containing RSV were able to neutralize 70.6 % of ROS (p<0.05). NPs encapsulating QUE/RSV showed to be able to decrease the total ROS by 81.16 % (p<0.05). Images taken by Fluorescence Microscopy revealed that encapsulated Nile Red was more efficient in permeating ex vivo porcine corneas than the free compound.After 5 minutes of contact the encapsulated Nile Red was observed in the corneal epithelium, while at longer contact times, 30 and 60 minutes, it was observed in the corneal stroma.
Conclusions :
Our results show that the ELR NPs containing QUE, RSV or both are biocompatible with HCE cells and possess excellent antioxidant properties in vitro.Improved permeation in ex vivo corneal tissues were noticed when the fluorescent drug model was encapsulated into the ELR NPs.This formulation strategy seems a promising method for topical delivery of QUE/RSV to the ocular surface.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.