RESUMO
A novel superparamagnetic nano-composite of Fe3O4@SiO2 coated by tragacanth gum (TG) as a natural product has been prepared. The obtained SiO2@Fe3O4@TG nanoparticles were characterized by Fourier transform infrared spectroscopy, energy dispersive X-ray analysis, scanning electron microscopy and dynamic light scattering analyzer. The magnetic nano-composite was applied for the loading and delivery of metformin, an oral diabetes medicine. The conditions for the loading of the drug were optimized by a central composite design optimization method. The maximum loading efficiency of the sorbent for metformin was obtained at pH 7 and its maximum in-vitro release was achieved at pH 1.6, using a phosphate-buffered saline medium. The loading capacity of the sorbent was dependent on the initial metformin concentration and exceeded to 19.6 mg/g in a 200 mg/L solution. A study of the adsorption isotherms for the drug indicated the best fitting into the Langmuir and Freundlich isotherms at the low and high metformin concentrations, respectively. The results indicated that the prepared Fe3O4@SiO2@TG adsorbent, as a non-toxic and low-cost sorbent, was quite appropriate for drug delivery applications.
