title: In vitro degradation and in vivo biocompatibility study of a new linear poly(urethane urea).
abstract: Segmented poly(urethane urea)s (PUUs) with hard segments derived only from methyl 2,6-diisocyantohexanoate (LDI) without the use of a chain extender have previously been described. These materials, which contain hard segments with multiple urea linkages, show exceptionally high strain capability (1600-4700%). In the study reported here, the rate and effect of hydrolysis of these materials were determined for gamma-sterilized and nonsterilized samples. Materials investigated contained PCL, PTMC, P(TMC-co-CL), P(CL-co-DLLA), or P(TMC-co-DLLA) as soft segments and, as well as their mechanical properties, changes in mass, inherent viscosity (I.V.), and thermal properties were studied over 20 weeks. Results showed that the degradation rate was dependant on the soft segment structure, with a higher rate of degradation for the polyester-dominating PUUs exhibiting a substantial loss in I.V. A tendency of reduction of tensile strength and strain hardening was seen for all samples. Also, loss in elongation at break was detected, for PUU-P(CL-DLLA) it went from 1600% to 830% in 10 weeks. Gamma radiation caused an initial loss in I.V. and induced more rapid hydrolysis compared with nonsterilized samples, except for PUU-PTMC. A cytotoxicity test using human fibroblasts demonstrated that the material supports cell viability. In addition, an in vivo biocompatibility study showed a typical foreign body reaction after 1 and 6 weeks.
authors.affiliation: Department of Materials Chemistry, Uppsala University, Uppsala, Sweden.
authors.forename: Basse
authors.initials: B
authors.lastname: Asplund
authors.forename: Cecilia
authors.initials: C
authors.lastname: Aulin
authors.forename: Tim
authors.initials: T
authors.lastname: Bowden
authors.forename: Niklas
authors.initials: N
authors.lastname: Eriksson
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Mathisen
authors.forename: Lars-Magnus
authors.initials: LM
authors.lastname: Bjursten
authors.forename: Jöns
authors.initials: J
authors.lastname: Hilborn
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D006868:Hydrolysis; D008297:Male; D008422:Materials Testing; D011140:Polyurethanes / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D013718:Tensile Strength; D014508:Urea / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D011140:Polyurethanes; D014508:Urea; C044690:polyetherurethane urea