title: A biodegradable thermoset polymer made by esterification of citric acid and glycerol.
abstract: A new biomaterial, a degradable thermoset polymer, was made from simple, economical, biocompatable monomers without the need for a catalyst. Glycerol and citric acid, nontoxic and renewable reagents, were crosslinked by a melt polymerization reaction at temperatures from 90 to 150°C. Consistent with a condensation reaction, water was determined to be the primary byproduct. The amount of crosslinking was controlled by the reaction conditions, including temperature, reaction time, and ratio between glycerol and citric acid. Also, the amount of crosslinking was inversely proportional to the rate of degradation. As a proof-of-principle for drug delivery applications, gentamicin, an antibiotic, was incorporated into the polymer with preliminary evaluations of antimicrobial activity. The polymers incorporating gentamicin had significantly better bacteria clearing of Staphylococcus aureus compared to non-gentamicin gels for up to 9 days.
authors.affiliation: Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, 44106.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Halpern
authors.forename: Richard
authors.initials: R
authors.lastname: Urbanski
authors.forename: Allison K
authors.initials: AK
authors.lastname: Weinstock
authors.forename: David F
authors.initials: DF
authors.lastname: Iwig
authors.forename: Robert T
authors.initials: RT
authors.lastname: Mathers
authors.forename: Horst A
authors.initials: HA
authors.lastname: von Recum
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D019343:Citric Acid / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D004951:Esterification; D005839:Gentamicins / Q000494:pharmacology; D005990:Glycerol / Q000737:chemistry*; D007700:Kinetics; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D011091:Polyesters / Q000138:chemical synthesis / Q000737:chemistry; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013211:Staphylococcus aureus / Q000187:drug effects; D013696:Temperature; D013818:Thermogravimetry
chemical_list: D000900:Anti-Bacterial Agents; D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D005839:Gentamicins; D011091:Polyesters; D011108:Polymers; D019343:Citric Acid; D005990:Glycerol
keywords: citric acid; controlled drug release; degradable polymers; glycerol; polyester