title: Hydrogel containing silica shell cross-linked micelles for ocular drug delivery.
abstract: Poly(2-hydroxyethyl methacrylate-methacrylic acid-ethylene glycol dimethacrylate) hydrogels loaded with silica shell cross-linked methoxy(polyethylene glycol)-block-polycaprolactone (MePEG-b-PCL) micelles with rod-like morphology were prepared as a potential soft contact lens material for the sustained release of ocular drugs. The silica shell cross-linked methoxy micelles (SSCMs) comprising a polycaprolactone core surrounded by a silica shell were synthesized and their size, morphology, stability, and drug release kinetics were evaluated. The relationships between the composition of the SSCM-loaded poly(2-hydroxyethyl methacrylate) (pHEMA)-based hydrogels and their transparency, surface wettability, and equilibrium water content were determined. Scanning electron microscopy (SEM) images of SSCM-hydrogel systems showed the presence of intact SSCMs within the hydrogel matrix. Dexamethasone acetate (DMSA), a hydrophobic ophthalmic drug, was loaded into the SSCMs prior to their incorporation into the hydrogels. In vitro release of DMSA from the SSCM-hydrogels, with varying drug loading levels, was observed for up to 30 days. Overall, the incorporation of rod-like SSCMs within pHEMA-based hydrogels provided sustained release over prolonged periods while maintaining optical transparency. This delivery system may be suitable for use as a therapeutic soft contact lens material.
authors.affiliation: Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada.
authors.forename: Changhai
authors.initials: C
authors.lastname: Lu
authors.forename: Roshan B
authors.initials: RB
authors.lastname: Yoganathan
authors.forename: Michael
authors.initials: M
authors.lastname: Kociolek
authors.forename: Christine
authors.initials: C
authors.lastname: Allen
mesh_terms: D060433:Administration, Ophthalmic; D003263:Contact Lenses, Hydrophilic; D003432:Cross-Linking Reagents / Q000008:administration & dosage / Q000737:chemistry* / Q000378:metabolism; D003907:Dexamethasone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D016503:Drug Delivery Systems / Q000379:methods*; D020100:Hydrogels / Q000008:administration & dosage / Q000737:chemistry* / Q000378:metabolism; D008823:Micelles; D012822:Silicon Dioxide / Q000008:administration & dosage / Q000737:chemistry* / Q000378:metabolism
chemical_list: D003432:Cross-Linking Reagents; D020100:Hydrogels; D008823:Micelles; D012822:Silicon Dioxide; D003907:Dexamethasone; C018038:dexamethasone acetate