title: 1H NMR investigation of thermally triggered insulin release from poly(N-isopropylacrylamide) microgels.
abstract: We describe investigations of insulin release from thermoresponsive microgels using variable temperature (1)H NMR. Microgel particles composed of poly(N-isopropylacrylamide) were loaded with the peptide via a swelling technique, and this method was compared to simple equilibrium partitioning. Variable temperature (1)H NMR studies suggest that the swelling loading method results in enhanced entrapment of the peptide versus equilibrium partitioning. A centrifugation-loading assay supports this finding. Pseudo-temperature jump (1)H NMR measurements suggest that the insulin release rate is partially decoupled from microgel collapse. These types of direct release investigations could prove to be useful methods in the future design of controlled macromolecule drug delivery devices.
authors.affiliation: School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Nolan
authors.forename: Leslie T
authors.initials: LT
authors.lastname: Gelbaum
authors.forename: L Andrew
authors.initials: LA
authors.lastname: Lyon
mesh_terms: D000096:Acetone / Q000737:chemistry; D000178:Acrylamides / Q000737:chemistry*; D001709:Biotechnology / Q000379:methods*; D002498:Centrifugation; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D016503:Drug Delivery Systems; D005782:Gels / Q000737:chemistry; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000737:chemistry*; D046911:Macromolecular Substances; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011108:Polymers / Q000737:chemistry; D013696:Temperature
chemical_list: D000178:Acrylamides; D003692:Delayed-Action Preparations; D005782:Gels; D007328:Insulin; D046911:Macromolecular Substances; D011108:Polymers; D000096:Acetone; C067295:N-isopropylacrylamide