title: Cyclodextrin/carbopol micro-scale interpenetrating networks (ms-IPNs) for drug delivery.
abstract: Cross-linking of hydroxypropyl-beta-cyclodextrin (HP beta CD) with ethyleneglycol diglycidylether (EGDE) in carbopol dispersions enabled the synthesis of cyclodextrin hydrogels with domains of interpenetrating acrylic microgels (micro-scale-IPNs) in a single step under mild conditions. As carbopol proportion increased, the hardness and compressibility of the ms-IPNs decreased, but their bioadhesion force and pH-responsiveness rose. Control HP beta CD hydrogel and ms-IPNs were loaded with estradiol and ketoconazole by immersion in drug suspensions, some of which were autoclaved to enhance (up to a 50%) drug/cyclodextrin affinity. ms-IPNs prepared with 0.8% or 1.0% carbopol showed the highest loading due to their greater swelling degree and, consequently, mesh size. The total loading of the ms-IPNs greatly exceeded (up to 200-fold) the amount dissolved in their aqueous phase, which highlights the main role of drug complexation with the cross-linked cyclodextrins. The affinity of the drug for HP beta CD sustained the release for several days; the rate being also dependent on carbopol content and on pH of the medium. Therefore, an adequate design of the HP beta CD/carbopol ms-IPNs provides a single material with tunable mechanical properties, in which the complexation ability of cyclodextrins is combined with the bioadhesive and pH-responsive properties of carbopol. The ms-IPNs are potentially useful as vehicles of relatively hydrophobic substances.
authors.affiliation: Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782-Santiago de Compostela, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Rodriguez-Tenreiro
authors.forename: Laura
authors.initials: L
authors.lastname: Diez-Bueno
authors.forename: Angel
authors.initials: A
authors.lastname: Concheiro
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Torres-Labandeira
authors.forename: Carmen
authors.initials: C
authors.lastname: Alvarez-Lorenzo
mesh_terms: D000180:Acrylic Resins; D003432:Cross-Linking Reagents / Q000008:administration & dosage / Q000737:chemistry; D003505:Cyclodextrins / Q000008:administration & dosage* / Q000737:chemistry; D016503:Drug Delivery Systems / Q000379:methods*; D008863:Microspheres; D011145:Polyvinyls / Q000008:administration & dosage* / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D003432:Cross-Linking Reagents; D003505:Cyclodextrins; D011145:Polyvinyls; C006912:carboxypolymethylene