Formulation and characterization of gentamicin-loaded albumin microspheres as a potential drug carrier for the treatment of E. coli K88 infections

The aim of this study was to formulate and characterize gentamicin-loaded albumin microspheres for their potential therapeutic use in E. coli K88 infections. Based on in vitro assays, it is proposed that microspheres may serve as a carrier of gentamicin and may provide localized antibacterial activity in the treatment of porcine colibacillosis. Gentamicin-albumin microspheres (GAM) were obtained using a water/oil (W/O) emulsion followed by cross-linking with different concentrations of glutaraldehyde. Electron microscopy showed spherical particles with indentations. The average size of the GAM was 10.5-12.3 μm. At pH 7.2, the release kinetics of gentamicin from the GAM was successfully described as an initial burst defined by a first order equation. Gentamicin release was unaffected by the glutaraldehyde concentrations used but was affected by acidic conditions. The behavior of gentamicin release from the GAM was not altered by digestion with trypsin and chymotrypsin at pH 7.2. Additionally, the concentration of gentamicin released from GAM to reach antibacterial activity was similar to that of free gentamicin against E. coli K88. This work shows the potential use of GAM as therapeutic vehicles of gentamicin to counteract intestinal infections in pigs.