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Lyophilization to improve drug delivery for chitosan‐calcium phosphate bone scaffold construct: A preliminary investigation
Author(s) -
Reves Benjamin T.,
Bumgardner Joel D.,
Cole Judith A.,
Yang Yunzhi,
Haggard Warren O.
Publication year - 2009
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.31390
Subject(s) - chitosan , bone morphogenetic protein 2 , elution , drug delivery , composite number , chemistry , alkaline phosphatase , chromatography , calcium , amikacin , materials science , biomedical engineering , antibiotics , composite material , biochemistry , medicine , organic chemistry , in vitro , enzyme
Lyophilization was evaluated in chitosan‐calcium phosphate microspheres and scaffolds to improve drug delivery of growth factors and antibiotics for orthopedic applications. The dual delivery of an antibiotic and a growth factor from a composite scaffold would be beneficial for treatment of complex fracture sites, such as comminuted fractures and segmental bone defects. The aim of this investigation was to increase the loading capacity of the composite by taking advantage of the increased porosity, due to lyophilization, and to produce an extended elution profile using a secondary chitosan‐bead coating. The physiochemical properties of the composite were investigated, and loading and elution studies were performed with alkaline phosphatase (ALP), bone morphogenetic protein‐2 (BMP‐2), and amikacin. Lyophilization was found to increase the surface area of scaffolds by over 400% and the porosity of scaffolds by 50%. Using ALP as a model protein, the loading capacity was increased by lyophilization from 4.3 ± 2.5 to 24.6 ± 3.6 μg ALP/mg microspheres, and the elution profile was extended by a supplemental chitosan coating. The loading capacity of BMP‐2 for composite microspheres was increased from 74.4 ± 3.7 to 102.1 ± 8.0 μg BMP‐2/g microspheres with lyophilization compared with nonlyophilized microspheres. The elution profiles of BMP‐2 and the antibiotic amikacin were not extended with the supplemental coating. Additional investigations are planned to improve these elution characteristics for growth factors and antibiotics. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009