title: On the behavior of HPMC/Theophylline matrices for controlled drug delivery.
abstract: Design of systems for oral controlled release of drug could take advantages from the knowledge of which phenomena take place. In this work matrices obtained by powders compression (50:50, hydroxypropyl methylcellulose, a swelling hydrogel, and theophylline, a model drug) were immersed in water at 37 degrees C, allowing the water uptake and the drug release by lateral surface, confining the cylindrical matrices between glass slides. The tablets, after given immersion times, were withdrawn, cut in several annuli, and subsequently analyzed for the drug and the water concentration radial profiles. The data confirmed the pseudo-diffusive nature of the process, allowing to give a deep insight into the drug release process from swellable hydrogel matrices. In particular, it was confirmed the presence of nonhomogeneous gel layer, rich in water and poor in drug, with a profile of drug concentration which agrees well with a pseudo-diffusion phenomenon.
authors.affiliation: Dipartimento di Scienze Farmaceutiche, Università degli Studi di Salerno, Via Ponte don Melillo, I-84084 Fisciano (SA), Italy.
authors.forename: Anna Angela
authors.initials: AA
authors.lastname: Barba
authors.forename: Matteo
authors.initials: M
authors.lastname: d'Amore
authors.forename: Sara
authors.initials: S
authors.lastname: Cascone
authors.forename: Serafina
authors.initials: S
authors.lastname: Chirico
authors.forename: Gaetano
authors.initials: G
authors.lastname: Lamberti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Titomanlio
mesh_terms: D004058:Diffusion; D004337:Drug Carriers; D016503:Drug Delivery Systems; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D065347:Hypromellose Derivatives; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D008956:Models, Chemical; D011208:Powders; D012995:Solubility; D013696:Temperature; D013806:Theophylline / Q000737:chemistry*; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D004337:Drug Carriers; D011208:Powders; D014867:Water; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D065347:Hypromellose Derivatives; D008747:Methylcellulose; D013806:Theophylline