RESUMO
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.
Assuntos
Amoxicilina/síntese química , Anti-Infecciosos/síntese química , Portadores de Fármacos/síntese química , Fármacos Gastrointestinais/síntese química , Fenômenos Magnéticos , Amoxicilina/farmacologia , Antibacterianos/síntese química , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Portadores de Fármacos/farmacologia , Composição de Medicamentos/métodos , Fármacos Gastrointestinais/farmacologia , Helicobacter pylori/efeitos dos fármacos , Microscopia Eletrônica de Varredura/métodos , Tamanho da Partícula , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Difração de Raios X/métodosRESUMO
Aqueous suspensions containing magnetic microparticles have been increasingly used in biosciences and biotechnology. This work describes an experimental procedure to produce superparamagnetic microparticles. The particles were prepared based on the coprecipitation of iron salts in alkaline medium. Afterwards, characterization was performed. Characterization data demonstrated that magnetite was the dominant phase in the analyzed sample, and 50% of them were in the size range of 0.5-5 microm. The results suggest that the experimental protocol provided a simple synthesis route to produce superparamagnetic microparticles. Such properties may be very useful for biotechnological purposes.
Assuntos
Biotecnologia/métodos , Óxido Ferroso-Férrico/química , Magnetismo , Tamanho da Partícula , Difração de Raios XRESUMO
This work evaluates an experimental set-up to coat superparamagnetic particles in order to protect them from gastric dissolution. First, magnetic particles were produced by coprecipitation of iron salts in alkaline medium. Afterwards, an emulsification/cross-linking reaction was carried out in order to produce magnetic polymeric particles. The sample characterization was performed by X-ray powder diffraction, laser scattering particle size analysis, optical microscopy, thermogravimetric analysis and vibrating sample magnetometry. In vitro dissolution tests at gastric pH were evaluated for both magnetic particles and magnetic polymeric particles. The characterization data have demonstrated the feasibility of the presented method to coat, and protect magnetite particles from gastric dissolution. Such systems may be very promising for oral administration.
Assuntos
Óxido Ferroso-Férrico/química , Magnetismo , Polímeros/química , Xilanos/química , Administração Oral , Preparações de Ação Retardada , Sistemas de Liberação de Medicamentos , Óxido Ferroso-Férrico/síntese química , Concentração de Íons de Hidrogênio , Lasers , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Espalhamento de Radiação , Solubilidade , Termogravimetria , Difração de Raios X , Zea maysRESUMO
The recent development of superconducting magnets has resulted in a huge increase in human exposure to very large static magnetic fields of up to several teslas (T). Considering the rapid advances in applications and the great increases in the strength of magnetic fields used, especially in magnetic resonance imaging, safety concerns about magnetic field exposure have become a key issue. This paper points out some of these safety concerns and gives an overview of the findings about this theme, focusing mainly on mechanisms of magnetic field interaction with living organisms and the consequent effects.