title: Development and evaluation of a floating multiparticulate gastroretentive system for modified release of AZT.
abstract: The aim of this study was to develop and evaluate a floating multiparticulate gastroretentive system for the modified release of zidovudine (AZT). AZT was used as a model drug water-soluble at therapeutic doses. The floating gastroretentive system was obtained by co-precipitation, after solvent diffusion and evaporation. The proposed system was evaluated in vitro for particle morphology, lag time and floating time, loading rate, release profile, and the release kinetic of AZT release. AZT's physico-chemical characteristics were evaluated by differential scanning calorimetry (DSC), X-ray diffraction (XDR) and infrared spectroscopy (IR). The particles obtained were sphere-shaped, hollow, and had porous walls. The floating was immediate, and floating time was higher than 12 h. The loading rate was 34.0 ± 9.0%. The system obtained had an extended release. DSC and XDR results showed a modification in AZT's solid state. IR spectroscopy revealed that the chemical structure of the AZT was unchanged. The hollow microballoons presented gastroretentive, floating, and extended-release properties.
authors.affiliation: Pharmaceutical Sciences Post-graduate Program, Sorocaba University, São Paulo, Brazil.
authors.forename: Valquíria Miwa Hanai
authors.initials: VM
authors.lastname: Yoshida
authors.forename: José Martins
authors.initials: JM
authors.lastname: de Oliveira Junior
authors.forename: Marcos Moisés
authors.initials: MM
authors.lastname: Gonçalves
authors.forename: Marta Maria Duarte Carvalho
authors.initials: MM
authors.lastname: Vila
authors.forename: Marco Vinícius
authors.initials: MV
authors.lastname: Chaud
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods* / Q000592:standards; D003692:Delayed-Action Preparations / Q000592:standards; D004353:Drug Evaluation, Preclinical / Q000379:methods / Q000592:standards; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism; D008863:Microspheres; D015215:Zidovudine / Q000737:chemistry* / Q000493:pharmacokinetics* / Q000592:standards
chemical_list: D003692:Delayed-Action Preparations; D015215:Zidovudine