Enzyme-mediated degradation of L-phenylalanine-based segmented polyurethaneureas

Two important parameters in the development and use of degradable biomaterials are related to the potential toxicity of the degradation products and the rate of material degradation when placed in the human body. This research focused on determining the degradation products from degradable segmented polyurethaneureas synthesized using LDI; a chain extender based on L-phenylalanine; and ϵ-polycaprolactone or polyethylene oxide. L-phenylalanine residues were incorporated into the polyurethane backbone in order to introduce sites for enzyme-mediated degradation. The polyurethanes were characterized using GPC and elemental analysis.; Degradation studies were carried out by incubating the polyurethanes for 8 weeks in tris buffered solutions containing chymotrypsin at 37°C and pH 8. Degradation was assessed by HPLC and MS. Three degradation products associated with the hard segment of the polyurethane were isolated and their chemical structures were determined. The study concludes that the hard segment region containing the amino-acids is effectively cleaved by the enzyme.