title: Physical gels of a carboxymethyl derivative of scleroglucan: synthesis and characterization.
abstract: A carboxymethyl derivative of scleroglucan (Scl-CM) was synthesized and characterized through FT-IR, 1H NMR and potentiometer titration. Rheological studies allowed evidencing the effect produced by the introduction of the carboxymethyl moiety on the native polymer. The mechanical spectrum of the scleroglucan solution showed a weak gel behaviour, while the derivative one looked like a system near the gel point, that evolved to a gel state depending on the concentration. This difference could be related to conformational changes due to the introduction of the negative charges on the chains. Different concentrations of Ca2+, added to the aqueous solutions of Scl-CM, were able to deeply modify the resulting system, showing a sharp transition toward a gel like behaviour. Acyclovir was loaded into the hydrogels obtained with different amounts of polymer and salt. The release rate of the drug from these systems was strictly related to both concentrations of salt and polymer. The obtained results suggest a possible employment of these new hydrogels for topical formulations or in situ implantation.
authors.affiliation: Dipartimento di Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Sapienza Università di Roma, Rome, Italy. mariaantonietta.casadei@uniroma1.it
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Casadei
authors.forename: Pietro
authors.initials: P
authors.lastname: Matricardi
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Fabrizi
authors.forename: Michelle
authors.initials: M
authors.lastname: Feeney
authors.forename: Patrizia
authors.initials: P
authors.lastname: Paolicelli
mesh_terms: D000212:Acyclovir / Q000008:administration & dosage / Q000032:analysis; D000998:Antiviral Agents / Q000008:administration & dosage / Q000032:analysis; D002118:Calcium / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D005936:Glucans / Q000008:administration & dosage* / Q000138:chemical synthesis / Q000737:chemistry*; D020100:Hydrogels; D007202:Indicators and Reagents; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D012212:Rheology
chemical_list: D000998:Antiviral Agents; D003692:Delayed-Action Preparations; D005936:Glucans; D020100:Hydrogels; D007202:Indicators and Reagents; C526264:carboxymethylscleroglucan; C045938:scleroglucan; D002118:Calcium; D000212:Acyclovir