title: Drug diffusion from disperse systems with a hydrophobically modified polysaccharide: Enhancer vs Franz cells.
abstract: This study assesses the capacity of a new hydrophobically modified polysaccharide -hydroxypropyl cellulose-methyl methacrylate - to control drug release in semisolid formulations. The dispersed systems contain the new polymer, Igepal CO520 as surfactant and theophylline as model drug at three concentrations (0.5, 1 and 1.5%, w/w). Drug release study shows that the systems containing 0.5% (w/w) of drug have faster release and higher diffusion coefficient than the other two concentrations. These results can be explained by two different structures ("relaxed" and "structured") found from a rheological point of view. Also, this paper compares two different devices for testing drug release and diffusion. It has been obtained more reliable and reproducible results with Enhancer Cell respect to Franz diffusion cell. In both cases, Fickian diffusion was the mechanism predominant for all systems. Finally, the utility of this polymer has been demonstrated to make three-dimensional gel structure and control theophylline release from systems in topical application.
authors.affiliation: Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, c/Profesor García González n° 2, 41012 Sevilla, Spain.
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Lucero
authors.forename: Carmen
authors.initials: C
authors.lastname: Claro
authors.forename: Marta
authors.initials: M
authors.lastname: Casas
authors.forename: María Rosa
authors.initials: MR
authors.lastname: Jiménez-Castellanos
mesh_terms: D002482:Cellulose / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry; D004058:Diffusion; D016503:Drug Delivery Systems; D005782:Gels / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D020366:Methylmethacrylate / Q000138:chemical synthesis / Q000737:chemistry; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011134:Polysaccharides / Q000138:chemical synthesis / Q000737:chemistry; D012212:Rheology; D012995:Solubility; D014867:Water / Q000737:chemistry
chemical_list: D005782:Gels; D011108:Polymers; D011134:Polysaccharides; D014867:Water; D020366:Methylmethacrylate; D011092:Polyethylene Glycols; D002482:Cellulose; C008079:hydroxypropylcellulose