A nonionic surfactant/chitosan micelle system in an innovative eye drop formulation

Area of Science:

• Drug Delivery Systems
• Ocular Pharmacology
• Materials Science

Background:

• Developing effective drug delivery systems for hydrophobic drugs like dexamethasone (DEX) is crucial for improving ocular bioavailability.
• Pluronic F127 (F127) and chitosan (CH) are biocompatible polymers with potential for micelle formation.

Purpose of the Study:

• To prepare and characterize micelle systems of F127 and CH loaded with DEX.
• To evaluate the in vitro release, Caco-2 cell permeability, and in vivo ocular bioavailability of DEX from these micelle systems.

Main Methods:

• Micelles were prepared using F127 and varying concentrations of CH with DEX.
• Characterization included hydrodynamic diameter, zeta-potential, drug loading, and in vitro release studies.
• In vitro transport across Caco-2 cell monolayers and in vivo ocular bioavailability in rabbits (measuring intraocular pressure and AUC) were assessed.

Main Results:

• F127/CH micelles exhibited suitable size (25.4–28.9 nm) and positive zeta-potential (+9.3–+17.6 mV).
• Chitosan significantly enhanced in vitro DEX release rate and Caco-2 cell permeability.
• In vivo studies showed a 1.7- to 2.4-fold increase in DEX ocular bioavailability compared to a DEX suspension, with good ocular tolerance.

Conclusions:

• F127/CH micelle systems provide a promising colloidal carrier for enhanced ocular delivery of dexamethasone.
• The combination of F127 and CH improves corneal permeability, leading to increased intraocular drug absorption and bioavailability.