Mitra Alami-milani - Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Parvin Zakeri-milani - Liver and Gastrointestinal Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Hadi Valizadeh - Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Roya Salehi - Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
Mitra Jelvehgari - Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran

Objective(s): Micelles have been studied as nanoparticulate drug delivery systems for improving the topical ocular delivery of hydrophobic drugs. The objective of this study was to develop and characterize dexamethasone-loaded polycaprolactone-polyethylene glycol-polycaprolactone (PCL-PEG-PCL) micelles to improve patient compliance and enhance the ocular bioavailability of poorly water-soluble drugs. Materials and Methods: The PCL-PEG-PCL copolymers were synthesized via the ring opening polymerization of ε-caprolactone in the presence of PEG. The resulting purified copolymers were characterized by GPC, NMR, FTIR, XRD and DSC. The critical micelle concentrations (CMCs) of the copolymers mentioned were determined. Dexamethasone was loaded into polymeric micelles by film hydration method, and dexamethasone-loaded micelles were characterized by TEM and DLS. Drug release kinetics and ex vivo corneal permeability were also determined. Results: The CMC of the synthetized copolymers was approximately ۰.۰۳ mg/ml. Aqueous solutions of the resulting copolymers (۴۰۰ mg/ml) rapidly formed a gel in situ at ۳۴ °C. The TEM results exhibited the successful formation of spherical micelles. The size of the prepared micelles was approximately ۴۰ nm. Formulated micelles sustained the release of the incorporated dexamethasone for ۵ days. Conclusion: Data from ex vivo permeability tests indicated that PCL-PEG-PCL micelles can be suitable candidates for the ocular delivery of dexamethasone and, likely, other hydrophobic drugs.

Block copolymer, Dexamethasone, Ocular drug delivery, Micelle, Critical micelle concentration