title: Synthetic PMMA-grafted polysaccharides as hydrophilic matrix for controlled-release forms.
abstract: This paper describes the rheological behavior of starch and cellulose acrylic graft copolymers synthesized with the aim of obtaining controlled-release excipients. The rheological characteristics determine the final release properties of matrix tablets. The study of the storage and loss moduli (G' and G", respectively) and the viscosity allowed us to know if the polymer behavior was that of a gel and, hence, if it could act as a barrier to drug diffusion. Since dynamic measurements showed a storage modulus higher than the loss modulus, we assessed that all the polymers were gels. Thus, knowing that all the graft copolymers had acceptable properties for compression, the release of theophylline as a model drug at different pH was studied. Polymers with higher absorption capacity, viscosity, and compactibility allowed formulations with slower release rates.
authors.affiliation: Dpto. de C. y T. de Polímeros, Fac. de Química, Universidad del País Vasco, San Sebastián, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Castellano
authors.forename: I
authors.initials: I
authors.lastname: Goñi
authors.forename: M C
authors.initials: MC
authors.lastname: Ferrero
authors.forename: A
authors.initials: A
authors.lastname: Muñoz
authors.forename: R
authors.initials: R
authors.lastname: Jiménez-Castellanos
authors.forename: M
authors.initials: M
authors.lastname: Gurruchaga
mesh_terms: D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000138:chemical synthesis / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D013806:Theophylline / Q000008:administration & dosage*; D014665:Vasodilator Agents / Q000008:administration & dosage*; D014783:Viscosity
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D011108:Polymers; D011134:Polysaccharides; D014665:Vasodilator Agents; D019904:Polymethyl Methacrylate; D013806:Theophylline