Chondroitin sulfate and L-Cysteine conjugate modified cationic nanostructured lipid carriers: Pre-corneal retention, permeability, and related studies for dry eye treatment

In this study, a novel bioadhesive material, a conjugate of chondroitin sulfate and L-cysteine (CS-Cys), was synthesized and modified on the surface of the cationic nanostructured lipid carriers loaded dexamethasone to prepare a novel nano-lipid ocular delivery system (Dex-CS-Cys-cNLC). Through the permeation and retention studies of isolated cornea, it was demonstrated that Dex-CS-Cys-cNLC has better corneal permeation and retention ability and can better overcome the barrier effect of the ocular surface. In addition, the fluorescent probe (RhB) was used to replace the drug, and fluorescence imaging was used to investigate the ocular surface retention ability of the formulation, and the results showed that CS-Cys-cNLC has stronger retention ability and can effectively prolong the time of drug action in the ocular surface. Dex-CS-Cys-cNLC was not irritating to rabbit eye tissues and was a safe delivery system. The results of rabbit dry eye pharmacodynamic experiments also showed that Dex-CS-Cys-cNLC could effectively alleviate dry eye symptoms in rabbits, effectively repair corneal damage, and improve the stability of tear film. All these experimental results suggest that Dex-CS-Cys-cNLC is a promising drug delivery carrier for the treatment of anterior segment of the eye disease.

Automated summary

A novel nano-lipid ocular delivery system (Dex-CS-Cys-cNLC) was prepared by synthesizing a conjugate of chondroitin sulfate and L-cysteine (CS-Cys) on the surface of cationic nanostructured lipid carriers loaded with dexamethasone. The permeation and retention studies of isolated cornea demonstrated that Dex-CS-Cys-cNLC had better corneal permeation and retention ability, overcoming the barrier effect of the ocular surface. The formulation showed stronger retention ability on the ocular surface and effectively prolonged drug action, as confirmed by fluorescence imaging.