title: Diffusion and mathematical modeling of release profiles from nanocarriers.
abstract: The aim of this work was to establish models and to differentiate the kinetic release behavior of drug models from nanocapsules, nanoemulsion and nanospheres by physico-chemical characterization and release experiments. SAXS analysis showed that the polymer is organized in the nanocapsules, while in the nanospheres the sorbitan monostearate is organized and acts as an impurity of the poly(epsilon-caprolactone) suggesting that constituents in these nanocarriers are differently organized. Formulations presented particle sizes ranging from 178 to 297 nm, probe content from 0.981 to 0.997 mg/mL, pH values from 4.90 to 5.10 and zeta potential from -37.9 to -51.9 mV. The kinetic experiments showed that the nanostructures present similar behaviors when the probe is adsorbed on the nanocarriers (indomethacin-loaded formulations). However, when the probe is entrapped within the nanocarriers (indomethacin ethyl ester-loaded formulations), nanocapsules, nanospheres and nanoemulsion presented different kinetic behaviors. Mathematical modeling of the release profiles was conducted, showing that the presence of the polymer increases the half-lives of the burst phases (5.9, 4.4 and 2.7 min) while the presence of the oil increases the half-lives of the sustained phases (288.8, 87.7 and 147.5 min) for nanocapsules, nanospheres and nanoemulsion, respectively.
authors.affiliation: Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Letícia
authors.initials: L
authors.lastname: Cruz
authors.forename: Leonardo U
authors.initials: LU
authors.lastname: Soares
authors.forename: Teresa Dalla
authors.initials: TD
authors.lastname: Costa
authors.forename: Graziela
authors.initials: G
authors.lastname: Mezzalira
authors.forename: Nadya P
authors.initials: NP
authors.lastname: da Silveira
authors.forename: Sílvia S
authors.initials: SS
authors.lastname: Guterres
authors.forename: Adriana R
authors.initials: AR
authors.lastname: Pohlmann
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D018360:Crystallography, X-Ray; D004058:Diffusion; D004337:Drug Carriers; D007213:Indomethacin / Q000031:analogs & derivatives* / Q000737:chemistry; D008956:Models, Chemical; D008962:Models, Theoretical; D036103:Nanotechnology; D009821:Oils / Q000737:chemistry; D011091:Polyesters / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D012995:Solubility; D013678:Technology, Pharmaceutical / Q000379:methods
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004337:Drug Carriers; D009821:Oils; D011091:Polyesters; D011108:Polymers; C507313:indomethacin ethyl ester; C016240:polycaprolactone; D007213:Indomethacin