Cyclodextrin/carbopol micro-scale interpenetrating networks (ms-IPNs) for drug delivery.
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.
Rodriguez-Tenreiro
Carmen
C
Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782-Santiago de Compostela, Spain.
Diez-Bueno
Laura
L
Concheiro
Angel
A
Torres-Labandeira
Juan J
JJ
Alvarez-Lorenzo
Carmen
C
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
D000180:Acrylic Resins; D003432:Cross-Linking Reagents; D003505:Cyclodextrins; D011145:Polyvinyls; C006912:carboxypolymethylene