Navegando por Autor "Pontes, Thales R. F."
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Artigo Design of Magnetic Polymeric Particles as a Stimulus-Responsive System for Gastric Antimicrobial Therapy(Springer Nature Switzerland AG, 2016-12-13) Carriço, Artur da Silva; Silva-Freitas, Erica L.; Pontes, Thales R. F.; Araújo-Neto, Rafael P.; Damasceno, Ítalo H. M.; Silva, Kátia L.; Carvalho, Juliana F.; Medeiros, Aldo C.; Silva, Rodolfo B.; Silva, Amanda K. A.; Morales, Marco A.; Egito, Eryvaldo S. T.; Dantas, Ana L.The treatment of peptic ulcers induced by H. pylori remains challenging due to the deep mucous layer location of bacteria preventing antimicrobial drug access. The present work aimed to design and evaluate in vitro dual responsive (both pH and magnetic field-sensitive) polymeric magnetic particles loaded with amoxicillin as a smart drug carrier for deep mucous layer penetration and in situ drug release. Magnetite particles were produced by the co-precipitation method and subsequently coated with the Eudragit®S100 and amoxicillin by using the spray-drying technique. The physicochemical characterization of the obtained particles was carried out by optical and scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption isotherms, and vibrating sample magnetometry. Additionally, drug release tests and antibacterial activity tests were evaluated in vitro. Microparticles presented 17.2 ± 0.4 μm in size and their final composition was 4.3 ± 1.5% of amoxicillin, 87.0 ± 2.3% of Eudragit, and 9.0 ± 0.3% of magnetite. They were both pH and magnetic field responsive while presenting antimicrobial activity. On one side, magnetic field responsiveness of particles is expected to prompt them to reach bacterium niche in deep mucous layer by means of magnetic forces. On the other side, pH responsiveness is expected to enable drug release in the neutral pH of the deep mucous layer, preventing undesired delivery in the acidic gastric lumen. Smart microparticles were designed presenting both pH and magnetic field responsiveness as well as antimicrobial activity. These may be promising assets for peptic ulcer treatment.Artigo Magnetite content evaluation on magnetic drug delivery systems by spectrophotometry: a technical note(Springer Nature Switzerland, 2011) Carriço, Artur da Silva; Silva-Freitas, Érica Lira; Carvalho, Juliana Fernandes; Pontes, Thales R. F.; Araújo Neto, Rafael P.; Egito, Eryvaldo Socrates TabosaMagnetic polymer particles have been widely used in alarge number of biotechnology and biomedicine applications(1–3). In modern pharmacy, basic investigations for themanufacturing and characterization of new dosage forms arefrequently performed using magneticfillers and drug carriers,which can be classified as the artificial sources of magneticfields. These sources are most typically based on magnetite,iron (III)γ-oxide, and barium ferrite (4)