title: In vitro release of metformin hydrochloride from sodium alginate/polyvinyl alcohol hydrogels.
abstract: Hydrogels, based on polysaccharides have found a number of applications as drug delivery carriers. In this work, hydrogels of full characterized sodium alginate (Mn 87,400g/mol) and commercial poly(vinyl alcohol) (PVA) sensitive to pH and temperature stimuli were obtained using a simple, controlled, green, low cost method based on freeze-thaw cycles. Stable hydrogels of sodium alginate/PVA with 0.5:1.5 and 1.0:1.0w/v concentrations showed very good swelling ratio values in distilled water (14 and 20g/g, respectively). Encapsulation and release of metformin hydrochloride in hydrogels of 1.0:1.0w/v sodium alginate/PVA was followed by UV spectroscopy. The hydrogel released a very low amount of metformin hydrochloride at pH 1.2; the highest release value (55%) was obtained after 6h at pH 8.0. Also, the release of metformin hydrochloride was studied by1H NMR spectroscopy, the temporal evolution of methyl group signals of metformin showed 30% of drug release after 3h.
authors.affiliation: Departamento de Ciencias del Ambiente, and los Materiales,Facultad de Química y Biología, Universidad de Santiago de Chile, Av. L. B. O'Higgins 3363, Santiago, Chile. Electronic address: fabian.martinez@usach.cl.
authors.forename: Fabián
authors.initials: F
authors.lastname: Martínez-Gómez
authors.affiliation: Departamento de Química de los Materiales,Facultad de Química y Biología, Universidad de Santiago de Chile, Av. L. B. O'Higgins 3363, Santiago, Chile.
authors.forename: Juan
authors.initials: J
authors.lastname: Guerrero
authors.affiliation: Departamento de Ciencias del Ambiente, and los Materiales,Facultad de Química y Biología, Universidad de Santiago de Chile, Av. L. B. O'Higgins 3363, Santiago, Chile.
authors.forename: Betty
authors.initials: B
authors.lastname: Matsuhiro
authors.affiliation: Departamento de Química de los Materiales,Facultad de Química y Biología, Universidad de Santiago de Chile, Av. L. B. O'Higgins 3363, Santiago, Chile.
authors.forename: Jorge
authors.initials: J
authors.lastname: Pavez
keywords: Hydrogel; Metformin hydrochloride; Poly(vinyl alcohol); Sodium alginate