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In vitro and in vivo release of nerve growth factor from biodegradable poly‐lactic‐ co ‐glycolic‐acid microspheres
Author(s) -
de Boer Ralph,
Knight Andrew M.,
Spinner Robert J.,
Malessy Martijn J. A.,
Yaszemski Michael J.,
Windebank Anthony J.
Publication year - 2010
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.32900
Subject(s) - glycolic acid , plga , in vivo , materials science , in vitro , lactic acid , kinetics , emulsion , controlled release , biophysics , biomedical engineering , nuclear chemistry , biochemistry , chemistry , nanotechnology , medicine , biology , genetics , physics , microbiology and biotechnology , quantum mechanics , bacteria
Abstract Regeneration of peripheral nerves after injury is suboptimal. We now report the long term delivery of nerve growth factor (NGF) by biodegradable poly‐lactic‐ co ‐glycolic acid (PLGA) microspheres in vitro and in vivo . Lactic to glycolic acid ratios of 50:50 and 85:15 were fabricated using the double emulsion solvent, evaporation technique. Three different inherent viscosities (0.1 dL g −1 : 1A, 0.4 dL g −1 : 4A, 0.7 dL g −1 : 7A) were analyzed. In vitro , release of NGF for 23 days was measured. Electron microscopy demonstrated intact spheres for at least 7 days (50:50 1A), 14 days (50:50 4A), or 35 days (50:50 7A and 85:15 7A). In vitro release kinetics was characterized by burst release, followed by release of NGF at a rate of 0.6–1.6% a day. Release curves for 50:50 1A and 85:15 7A differed significantly from other compositions ( p < 0.01). In vivo , release was characterized by a novel radionuclide tracking assay. Release rates varied from 0.9 to 2.2% per day with linear kinetics. All but the 85:15 type of spheres showed different release profiles in vivo compared to in vitro conditions. On the basis of the surface morphology and release profiles, we found microspheres fabricated from 50:50 4A PLGA to be best suited for the use in a rat sciatic nerve injury model. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.