Physicochemical characterization of spray-dried PLGA/PEG microspheres, and preliminary assessment of biological response

AbstractContext: The use of spray-drying to prepare blended PLGA:PEG microspheres with lower immune detection.Objective: To study physical properties, polymer miscibility and alveolar macrophage response for blended PLGA:PEG microspheres prepared by a laboratory-scale spray-drying process.Methods: Microspheres were prepared by spray-drying 0–20% w/w ratios of PLGA 65:35 and PEG 3350 in dichloromethane. Particle size and morphology was studied using scanning electron microscopy. Polymer miscibility and residual solvent levels evaluated by thermal analysis (differential scanning calorimetry – DSC and thermogravimetric analysis – TGA). Immunogenicity was assessed in vitro by response of rat alveolar macrophages (NR8383) by the MTT-based cell viability assay and reactive oxygen species (ROS) detection.Results: The spray dried particles were spherical, with a size range of about 2–3 µm and a yield of 16–60%. Highest yield was obtained at 1% PEG concentration. Thermal analysis showed a melting peak at 59 °C (en...