Biodegradable gelatin-based nanospheres as pH-responsive drug delivery systems
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Native gelatin, N,N′-ethylenebisacrylamide, and sodium methacrylate were inserted into a spherical crosslinked structure by a solvent-free emulsion polymerization method, in which sunflower seed oil containing different amounts of lecithin was selected as continuous phase. Nanogels were characterized by morphological analysis, particle size distribution, and determination of swelling degree. Different dimensional distributions (100–500 nm) and water affinities were obtained by varying the amount of surfactant in the polymerization feed. Nanogels were non-toxic on human bone marrow mesenchymal stromal cells and enzymatically stable in the gastric tract, with weight losses ranging from 58 to 20 % in pancreatin solution. Release profiles of diclofenac sodium salt from the nanogels were evaluated at different pH and found to depend on crosslinking degree and drug–polymer interactions; while in pancreatin solution, a complete release of the drug was observed. The release mechanism and the diffusional contribution were evaluated by semiempirical equations.
KeywordsGelatin nanospheres PH-responsive hydrogels Biodegradable Biocompatibility Drug delivery
This study was financially supported by University of Calabria funds. Financial support of Regional Operative Program (ROP) Calabria ESF 2007/2013—IV Axis Human Capital—Operative Objective M2—Action D.5 is also gratefully acknowledged. Authors thank Dr. Pacini from the Hematology Division, Department of Oncology, Transplants and New Advances in Medicine, University of Pisa, for providing hBM-MSCs.
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