High encapsulation efficiency of sodium alendronate in eudragit S100/HPMC blend microparticles

The hydrophilic drug sodium alendronate was encapsulated in blended microparticles of Eudragit® S100 and Methocel® F4M or Methocel® K100LV. Both formulations prepared by spray-drying showed spherical collapsed shape and smooth surface, encapsulation efficiencies of 85 and 82% and mean diameters of 11.7 and 8.4 µm, respectively. At pH 1.2, in vitro dissolution studies showed good gastro-resistance for both formulations. At pH 6.8, the sodium alendronate release from the microparticles was delayed and was controlled by Fickian diffusion. In conclusion, the prepared microparticles showed high encapsulation efficiency of sodium alendronate presenting gastro-resistance and sustained release suitable for its oral administration.

Micropartículas nanorrevestidas contendo um fármaco modelo hidrofóbico: preparação em etapa única e caracterização biofarmacêutica

The aim of this work was to prepare and characterize spray-dried nanocapsule-coated microparticles obtained in one step, using indomethacin as a hydrophobic drug model and poly(e-caprolactone) or Eudragit® RS100, as polymers. Nanocapsule-coated microparticles showed micrometric mean sizes (10 - 15 µm) and a reduced surface area (75 - 85 m²g-1) compared to the raw material (214 m²g-1). Microparticles coated with Eudragit® RS100-nanocapsules showed a better control of the drug release. The release profiles fit to the monoexponetial model and to the Power Law. The mechanism of the indomethacin release from the microparticles is non-Fickian and depends on the particles desagglomeration.

ANÁLISES FÍSICO-QUÍMICAS DE BIOFILMES DE SULFATO DE CONDROITOINA MODIFICADO

Numerous investigations are dedicated to the research and development of new polymer materials destined for innovation in pharmaceutical forms. The application of these technological resources has allowed the commercialization of new therapeutic systems for modified drug release. This investigation aimed to evaluate the association of modified chondroitin sulfate with an insoluble polymer, Eudragit® RS 30 D, widely available in the pharmaceutical market. Isolated films were prepared by the evaporation process using a Teflon® plate. The aqueous dispersions (4% m/v) of synthetic polymer received the addition of modified chondroitin sulfate at different ratios. The interactions of the polymer chains in the blends were physicochemically characterized by means of Fourier transform infrared spectroscopy, thermal analyses, differential scanning calorimetry, thermogravimetry and scanning electron microscopy combined with hydration and assays in alkaline pH. The results showed appropriate properties of the coating materials for solid oral forms intended for drug deliver in specific environments.