title: Soft hydrogels interpenetrating silicone--A polymer network for drug-releasing medical devices.
abstract: Materials for the next generation of medical devices will require not only the mechanical stability of current devices, but must also possess other properties such as sustained release of drugs in a controlled manner over a prolonged period of time. This work focuses on creating such a sophisticated material by forming an interpenetrating polymer network (IPN) material through modification of silicone elastomers with a poly(2-hydroxyethyl methacrylate) (PHEMA)-based hydrogel. IPN materials with a PHEMA content in the range of 13%-38% (w/w) were synthesized by using carbon dioxide-based solvent mixtures under high pressure. These IPNs were characterized with regard to microstructure as well as ability of the hydrogel to form a surface-connected hydrophilic carrier network inside the silicone. A critical limit for hydrogel connectivity was found both via simulation and by visualization of water uptake in approximately 25% (w/w) PHEMA, indicating that entrapment of gel occurs at low gel concentrations. The optimized IPN material was loaded with the antibiotic ciprofloxacin, and the resulting drug release was shown to inhibit bacterial growth when placed on agar, thus demonstrating the potential of this IPN material for future applications in drug-releasing medical devices.
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100, Copenhagen, Denmark.
authors.forename: Søren L
authors.initials: SL
authors.lastname: Steffensen
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100, Copenhagen, Denmark.
authors.forename: Merete H
authors.initials: MH
authors.lastname: Vestergaard
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100, Copenhagen, Denmark.
authors.forename: Eva H
authors.initials: EH
authors.lastname: Møller
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100, Copenhagen, Denmark.
authors.forename: Minna
authors.initials: M
authors.lastname: Groenning
authors.affiliation: BioModics ApS, DK-2800, Lyngby, Denmark.
authors.forename: Martin
authors.initials: M
authors.lastname: Alm
authors.affiliation: Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100, Copenhagen, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Franzyk
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100, Copenhagen, Denmark.
authors.forename: Hanne M
authors.initials: HM
authors.lastname: Nielsen
mesh_terms: D000818:Animals; D002939:Ciprofloxacin / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D004343:Drug Implants / Q000737:chemistry / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D051379:Mice; D041681:NIH 3T3 Cells; D011102:Polyhydroxyethyl Methacrylate / Q000737:chemistry*; D012828:Silicones / Q000737:chemistry*
chemical_list: D004343:Drug Implants; D020100:Hydrogels; D012828:Silicones; D011102:Polyhydroxyethyl Methacrylate; D002939:Ciprofloxacin
keywords: antibacterial; controlled drug delivery; hydrogel; interpenetrating network material; medical device; silicone elastomer