title: Biodegradable hydrogels obtained by photocrosslinking of dextran and polyaspartamide derivatives.
abstract: The functionalization of dextran with glycidyl methacrylate (GMA) leads to the formation of a derivative that generates hydrogels for irradiation at 365nm. The effects of various polymer concentrations and irradiation times on the yield and the properties of the obtained hydrogels are reported. The networks have been characterized by FT-IR spectra, dimensional analysis and swelling measurements carried out at different pH values. In vitro studies suggest that all samples undergo a partial chemical hydrolysis, whereas the incubation with dextranases causes a total degradation whose rate depends on the degree of crosslinking. In addition, aqueous solutions of functionalized dextran have been irradiated in the presence of PHG (PHEA-GMA), i.e. the copolymer obtained by the reaction of alpha,beta-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) with GMA. The crosslinking reaction leads to the formation of new networks containing both polymers whose properties have been investigated. To evaluate the processes which occur during UV irradiation, the sol fractions have been purified and characterized by FT-IR and 1H-NMR analyses. Finally, the suitability of hydrogels deriving from functionalized dextran, crosslinked alone or in the presence of PHG, for drug delivery systems has been investigated choosing theophylline as a model drug.
authors.affiliation: Dipartimento di Chimica e Tecnologie Farmaceutiche, Università di Palermo, Via Archirafi 32, 90123, Palermo, Italy. giopitar@unipa.it
authors.forename: G
authors.initials: G
authors.lastname: Pitarresi
authors.forename: F S
authors.initials: FS
authors.lastname: Palumbo
authors.forename: G
authors.initials: G
authors.lastname: Giammona
authors.forename: M A
authors.initials: MA
authors.lastname: Casadei
authors.forename: F
authors.initials: F
authors.lastname: Micheletti Moracci
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000494:pharmacology; D003270:Contraceptive Agents; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000494:pharmacology; D003911:Dextrans / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D010455:Peptides / Q000737:chemistry*; D011102:Polyhydroxyethyl Methacrylate / Q000031:analogs & derivatives* / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013806:Theophylline / Q000737:chemistry; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D001672:Biocompatible Materials; D003270:Contraceptive Agents; D003432:Cross-Linking Reagents; D003911:Dextrans; D020100:Hydrogels; D010455:Peptides; D011108:Polymers; C008965:alpha,beta-poly((2-hydroxyethyl)-aspartamide); D011102:Polyhydroxyethyl Methacrylate; C023037:poly(2-hydroxyethyl acrylate); C017645:polyaspartate; D017438:Bisphenol A-Glycidyl Methacrylate; D013806:Theophylline