title: pH-sensitive hydrogels of dextran: synthesis, characterization and in vivo studies.
abstract: pH-Sensitive hydrogels of dextran were synthesized by photochemical cross-linking reaction of methacrylate dextran (DEX-MA) at different derivatization degree, functionalized with acidic residues through reaction with phthalic anhydride. The hydrogels were characterized by FT-IR spectra, swelling measurements, experiments of chemical and enzymatic hydrolyses. The swelling data agreed with the formation of networks having pH-sensitive behaviour. This property was confirmed by the morphological examination performed by scanning electron microscopy on samples maintained in media at different pH. (S)-4-Isobutyl-2-phenylpropionic acid (ibuprofen) was loaded into the polymeric matrices. The analysis of the release profiles of the drug from the three networks showed that all the matrices were able to retain ibuprofen during the transit through the stomach, releasing it in a sustained way in the intestinal tract at a rate strictly dependent on the derivatization degree in methacrylic groups. In vivo studies verified the biocompatibility of the materials. Moreover, when the matrix loaded with ibuprofen was administered to rats, it was able to protect them from the ulcerogenic effects of the drug.
authors.affiliation: Dipartimento di Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Sapienza Universita di Roma, Rome, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Giannuzzo
authors.forename: Federica
authors.initials: F
authors.lastname: Corrente
authors.forename: Michelle
authors.initials: M
authors.lastname: Feeney
authors.forename: Luigi
authors.initials: L
authors.lastname: Paoletti
authors.forename: Patrizia
authors.initials: P
authors.lastname: Paolicelli
authors.forename: Beatrice
authors.initials: B
authors.lastname: Tita
authors.forename: Federica
authors.initials: F
authors.lastname: Vitali
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Casadei
mesh_terms: D000818:Animals; D003911:Dextrans / Q000138:chemical synthesis / Q000737:chemistry*; D016503:Drug Delivery Systems; D020100:Hydrogels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007052:Ibuprofen / Q000009:adverse effects / Q000737:chemistry; D008297:Male; D008689:Methacrylates / Q000138:chemical synthesis*; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D051381:Rats; D017207:Rats, Sprague-Dawley; D013270:Stomach / Q000473:pathology; D013272:Stomach Diseases / Q000139:chemically induced / Q000517:prevention & control
chemical_list: D003911:Dextrans; D020100:Hydrogels; D008689:Methacrylates; C534732:dextran methacylate phthalate; D007052:Ibuprofen