title: Triphasic release model for multilayered gelatin coatings that can recreate growth factor profiles during wound healing.
abstract: Multilayered gelatin coatings were created to mimic growth factor profiles that normally occur during fracture healing. A model was developed to relate crosslinking and loading of individual layers to protein release. Modeling was simplified by dividing release profiles into three phases. The diffusion-controlled phase was determined by calculating periods of constant diffusivity for each homogeneous layer within devices. Diffusivity was a power law function of crosslinking. Fick's second law of diffusion was then used to determine release during the diffusion-controlled phase. Secondary diffusivity was determined by summing resistances of each successive homogeneous layer. The initial burst phase was defined as events proceeding the diffusion-controlled phase. Percentage of drug burst was a linear function of crosslinking. Release during the degradation-controlled phase, events following diffusion-controlled phase, was estimated based on first order hydrolysis of crosslinks. The model predicted time-variant release of differently labeled protein measured experimentally, and it can be used to design coatings to recreate the cascade of biomolecules that determine natural bone repair.
authors.affiliation: Wenner-Gren Lab, Center for Biomedical Engineering, University of Kentucky, Lexington 40506-0070, USA.
authors.forename: A T
authors.initials: AT
authors.lastname: Raiche
authors.forename: D A
authors.initials: DA
authors.lastname: Puleo
mesh_terms: D000818:Animals; D020099:Coated Materials, Biocompatible / Q000008:administration & dosage / Q000138:chemical synthesis / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D046508:Culture Techniques; D003692:Delayed-Action Preparations / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004058:Diffusion / Q000187:drug effects; D050723:Fractures, Bone / Q000628:therapy; D005780:Gelatin / Q000008:administration & dosage / Q000737:chemistry*; D005976:Glutaral / Q000494:pharmacology; D006133:Growth Substances / Q000378:metabolism*; D008962:Models, Theoretical; D009113:Muramidase / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D014945:Wound Healing
chemical_list: D020099:Coated Materials, Biocompatible; D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D006133:Growth Substances; D005780:Gelatin; D009113:Muramidase; D005976:Glutaral