Hydrogels Containing Core Cross-Linked Block Co-Polymer Micelles

Poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogels loaded with core cross-linked PEG-b-PCL micelles with different morphologies (spherical and rod-like) were prepared and evaluated for use as drugeluting soft contact lenses. The relationship between the composition of micelle-loaded pHEMA hydrogels and properties such as transparency and swelling were determined. The incorporation of core crosslinked micelles into pHEMA hydrogels led to the formation of different internal nanostructures which were dependent on the amount and morphology of the micelles added. 7-Hydroxy-9H-(1,3-dichloro-9,9'-dimethylacridin-2-one) (DDAO), a hydrophobic fluorescent dye, was loaded into the micelles prior to their incorporation within the hydrogel matrix. The in vitro release of DDAO demonstrated the potential of the micelles/pHEMA hydrogels to provide controlled drug delivery for at least 14 days. This study demonstrates the feasibility of both chemical and physical incorporation of block co-polymer micelles within pHEMA hydrogels as a means to achieve sustained release of drugs for potential application in ophthalmic therapies.