Elastase-induced hydrolysis of synthetic solid substrates: poly(ester-urea-urethane) and poly(ether-urea-urethane)

Human neutrophil elastase (HNE) and porcine pancreatic elastase (PPE) were incubated with two radiolabelled model poly(urethane)s, a poly(ester-urea-urethane) containing [ 14C]toluene diisocyanate ([14C]TDI), poly(caprolactone) (PCL) and ethylenediamine (ED), and a poly(ether-urea-urethane) containing [ 14C]TDI, poly(tetramethylene oxide) (PTMO) and ED. Ten-fold more radioactive carbon was released when PPE was incubated with [ 14C]TDI/PCL/ED than when HNE was used. The PPE-induced radioactive carbon release was significantly reduced by a specific elastase inhibitor. Ten-fold less radioactive carbon was released when [ 14 C]TDI/PTMO/ED was incubated with PPE as compared to [ 14C]TDI/PCL/ED. Since neutrophils, which contain elastolytic activity, are present during the inflammatory response, the stability of biomaterials used in implanted devices may be affected.