title: Do cyclodextrins bound to dextran microspheres act as sustained delivery systems of drugs?
abstract: The use of cyclodextrins (CDs) for controlled delivery of drugs is largely presented in the literature. However, the question of whether CDs themselves linked to a polymeric network are able to sustain the release of drugs still persists. Here, CD immobilization within dextran microspheres is reported, and CD-dextran complexes were packed in a glass column and then, the retention time of different drugs and drug model compounds was determined by liquid chromatography. The release profiles of drugs and of drug model compounds (indole, 3-nitrophenol, p-hydroxybenzoic acid, diclofenac), characterized by different values of the retention time (high, moderate or low), were investigated. The release rates were quite high even for drugs that exhibit very high retention time (high association equilibrium constant). Moreover, the volume of the release fluid strongly influences the rate of drug release. As a whole, "the sink conditions" must be continuously maintained, since at each drug concentration in the release medium, equilibrium occurs between the free and the CD-bound drug.
authors.affiliation: Department of Natural Polymers, Bioactive and Biocompatible Materials, "Petru Poni" Institute of Macromolecular Chemistry, Iassy 700487, Romania.
authors.forename: Marieta
authors.initials: M
authors.lastname: Constantin
authors.affiliation: Department of Natural Polymers, Bioactive and Biocompatible Materials, "Petru Poni" Institute of Macromolecular Chemistry, Iassy 700487, Romania.
authors.forename: Sanda
authors.initials: S
authors.lastname: Bucatariu
authors.affiliation: Department of Natural Polymers, Bioactive and Biocompatible Materials, "Petru Poni" Institute of Macromolecular Chemistry, Iassy 700487, Romania.
authors.forename: Valeria
authors.initials: V
authors.lastname: Harabagiu
authors.affiliation: Interdepartmental Laboratory for Electron Microscopy, University Roma Tre, Roma I-00146, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Ascenzi
authors.affiliation: Department of Natural Polymers, Bioactive and Biocompatible Materials, "Petru Poni" Institute of Macromolecular Chemistry, Iassy 700487, Romania. Electronic address: ghefun@icmpp.ro.
authors.forename: Gheorghe
authors.initials: G
authors.lastname: Fundueanu
mesh_terms: D002626:Chemistry, Pharmaceutical; D002853:Chromatography, Liquid; D003505:Cyclodextrins / Q000737:chemistry*; D003692:Delayed-Action Preparations; D003911:Dextrans / Q000737:chemistry*; D004008:Diclofenac / Q000737:chemistry*; D004337:Drug Carriers; D007211:Indoles / Q000737:chemistry*; D007700:Kinetics; D008863:Microspheres; D008956:Models, Chemical; D009596:Nitrophenols / Q000737:chemistry*; D010226:Parabens / Q000737:chemistry*; D012995:Solubility; D013678:Technology, Pharmaceutical / Q000379:methods; D047391:alpha-Cyclodextrins / Q000737:chemistry; D047392:beta-Cyclodextrins / Q000737:chemistry; D047408:gamma-Cyclodextrins / Q000737:chemistry
chemical_list: D003505:Cyclodextrins; D003692:Delayed-Action Preparations; D003911:Dextrans; D004337:Drug Carriers; D007211:Indoles; D009596:Nitrophenols; D010226:Parabens; D047391:alpha-Cyclodextrins; D047392:beta-Cyclodextrins; D047408:gamma-Cyclodextrins; D004008:Diclofenac; C030374:indole; C038193:4-hydroxybenzoic acid; C049017:3-nitrophenol
keywords: Association constant; Cyclodextrin; Drug release; Inclusion complex; Liquid chromatography